Here's some simple batch files that I've been using to integrate updates and drivers into all indexes of Win7 source files before building .iso.
I thought I'd share them for others.
Make sure to execute these batch files by right-clicking and selecting "Run as administrator".
Set the paths to whatever you like, just be sure to NOT use a trailing backslash in the path (i.e. C:\mnt instead of C:\mnt\ )
To download the patches, I use Windows Updates Downloader with current download lists from this post (not 100% complete, but a great start)
For drivers, I separate my folders into boot & main. Boot drivers are integrated into the boot.wim (index 2) and for me only contain dpms.
Enjoy! 
updates-x86.bat
@echo off
::Set Paths
:: Do NOT use trailing backslash in path (i.e. C:\mnt instead of C:\mnt\ )
:Path to mount folder
set mnt=C:\Tools\W7\mount
:Path to source .wim
set src=C:\Tools\W7\Source\x86\sources
:Path to update packages
set updates1=C:\Tools\W7\Updates\Windows_7_SP1_x86_ENU\Critical_Updates
set updates2=C:\Tools\W7\Updates\Windows_7_SP1_x86_ENU\Important_Updates
set updates3=C:\Tools\W7\Updates\Windows_7_SP1_x86_ENU\Optional_Updates
cls
dism /Mount-Wim /WimFile:%src%\install.wim /index:5 /MountDir:%mnt%
dism /Image:%mnt% /Add-Package /PackagePath:%updates1%
dism /Image:%mnt% /Add-Package /PackagePath:%updates2%
dism /Image:%mnt% /Add-Package /PackagePath:%updates3%
dism /Unmount-Wim /MountDir:%mnt% /commit
dism /Mount-Wim /WimFile:%src%\install.wim /index:4 /MountDir:%mnt%
dism /Image:%mnt% /Add-Package /PackagePath:%updates1%
dism /Image:%mnt% /Add-Package /PackagePath:%updates2%
dism /Image:%mnt% /Add-Package /PackagePath:%updates3%
dism /Unmount-Wim /MountDir:%mnt% /commit
dism /Mount-Wim /WimFile:%src%\install.wim /index:3 /MountDir:%mnt%
dism /Image:%mnt% /Add-Package /PackagePath:%updates1%
dism /Image:%mnt% /Add-Package /PackagePath:%updates2%
dism /Image:%mnt% /Add-Package /PackagePath:%updates3%
dism /Unmount-Wim /MountDir:%mnt% /commit
dism /Mount-Wim /WimFile:%src%\install.wim /index:2 /MountDir:%mnt%
dism /Image:%mnt% /Add-Package /PackagePath:%updates1%
dism /Image:%mnt% /Add-Package /PackagePath:%updates2%
dism /Image:%mnt% /Add-Package /PackagePath:%updates3%
dism /Unmount-Wim /MountDir:%mnt% /commit
dism /Mount-Wim /WimFile:%src%\install.wim /index:1 /MountDir:%mnt%
dism /Image:%mnt% /Add-Package /PackagePath:%updates1%
dism /Image:%mnt% /Add-Package /PackagePath:%updates2%
dism /Image:%mnt% /Add-Package /PackagePath:%updates3%
dism /Unmount-Wim /MountDir:%mnt% /commit
echo .........................................
echo Update integration complete
pause
exit
updates-x64.bat
@echo off
::Set Paths
:: Do NOT use trailing backslash in path (i.e. C:\mnt instead of C:\mnt\ )
:Path to mount folder
set mnt=C:\Tools\W7\mount
:Path to source .wim
set src=C:\Tools\W7\Source\x64\sources
:Path to update packages
set updates1=C:\Tools\W7\Updates\Windows_7_SP1_x64_ENU\Critical_Updates
set updates2=C:\Tools\W7\Updates\Windows_7_SP1_x64_ENU\Important_Updates
set updates3=C:\Tools\W7\Updates\Windows_7_SP1_x64_ENU\Optional_Updates
::Do NOT modify anything below this line unless you know what you are doing!
cls
dism /Mount-Wim /WimFile:%src%\install.wim /index:4 /MountDir:%mnt%
dism /Image:%mnt% /Add-Package /PackagePath:%updates1%
dism /Image:%mnt% /Add-Package /PackagePath:%updates2%
dism /Image:%mnt% /Add-Package /PackagePath:%updates3%
dism /Unmount-Wim /MountDir:%mnt% /commit
dism /Mount-Wim /WimFile:%src%\install.wim /index:3 /MountDir:%mnt%
dism /Image:%mnt% /Add-Package /PackagePath:%updates1%
dism /Image:%mnt% /Add-Package /PackagePath:%updates2%
dism /Image:%mnt% /Add-Package /PackagePath:%updates3%
dism /Unmount-Wim /MountDir:%mnt% /commit
dism /Mount-Wim /WimFile:%src%\install.wim /index:2 /MountDir:%mnt%
dism /Image:%mnt% /Add-Package /PackagePath:%updates1%
dism /Image:%mnt% /Add-Package /PackagePath:%updates2%
dism /Image:%mnt% /Add-Package /PackagePath:%updates3%
dism /Unmount-Wim /MountDir:%mnt% /commit
dism /Mount-Wim /WimFile:%src%\install.wim /index:1 /MountDir:%mnt%
dism /Image:%mnt% /Add-Package /PackagePath:%updates1%
dism /Image:%mnt% /Add-Package /PackagePath:%updates2%
dism /Image:%mnt% /Add-Package /PackagePath:%updates3%
dism /Unmount-Wim /MountDir:%mnt% /commit
echo .........................................
echo Update integration complete
pause
exit
drivers-x86.bat
@echo off
::Set Paths
:: Do NOT use trailing backslash in path (i.e. C:\mnt instead of C:\mnt\ )
:Path to mount folder
set mnt=C:\Tools\W7\mount
:Path to source .wim
set src=C:\Tools\W7\Source\x86\sources
:Path to driver packages
set driver-boot=C:\Tools\Drivers\Boot\x86
set driver-main=C:\Tools\Drivers\x86
::Do NOT modify anything below this line unless you know what you are doing!
cls
Dism /Mount-Wim /WimFile:%src%\BOOT.WIM /index:2 /MountDir:%mnt%
Dism /image:%mnt% /Add-Driver /driver:%driver-boot% /recurse
dism /Unmount-Wim /MountDir:%mnt% /commit
dism /Mount-Wim /WimFile:%src%\install.wim /index:5 /MountDir:%mnt%
Dism /image:%mnt% /Add-Driver /driver:%driver-main% /recurse
dism /Unmount-Wim /MountDir:%mnt% /commit
dism /Mount-Wim /WimFile:%src%\install.wim /index:4 /MountDir:%mnt%
Dism /image:%mnt% /Add-Driver /driver:%driver-main% /recurse
dism /Unmount-Wim /MountDir:%mnt% /commit
dism /Mount-Wim /WimFile:%src%\install.wim /index:3 /MountDir:%mnt%
Dism /image:%mnt% /Add-Driver /driver:%driver-main% /recurse
dism /Unmount-Wim /MountDir:%mnt% /commit
dism /Mount-Wim /WimFile:%src%\install.wim /index:2 /MountDir:%mnt%
Dism /image:%mnt% /Add-Driver /driver:%driver-main% /recurse
dism /Unmount-Wim /MountDir:%mnt% /commit
dism /Mount-Wim /WimFile:%src%\install.wim /index:1 /MountDir:%mnt%
Dism /image:%mnt% /Add-Driver /driver:%driver-main% /recurse
dism /Unmount-Wim /MountDir:%mnt% /commit
echo .........................................
echo Driver integration complete
pause
exit
drivers-x64.bat
@echo off
::Set Paths
:: Do NOT use trailing backslash in path (i.e. C:\mnt instead of C:\mnt\ )
:Path to mount folder
set mnt=C:\Tools\W7\mount
:Path to source .wim
set src=C:\Tools\W7\Source\x64\sources
:Path to driver packages
set driver-boot=C:\Tools\Drivers\Boot\x64
set driver-main=C:\Tools\Drivers\x64
::Do NOT modify anything below this line unless you know what you are doing!
cls
Dism /Mount-Wim /WimFile:%src%\BOOT.WIM /index:2 /MountDir:%mnt%
Dism /image:%mnt% /Add-Driver /driver:%driver-boot% /recurse
dism /Unmount-Wim /MountDir:%mnt% /commit
dism /Mount-Wim /WimFile:%src%\install.wim /index:4 /MountDir:%mnt%
Dism /image:%mnt% /Add-Driver /driver:%driver-main% /recurse
dism /Unmount-Wim /MountDir:%mnt% /commit
dism /Mount-Wim /WimFile:%src%\install.wim /index:3 /MountDir:%mnt%
Dism /image:%mnt% /Add-Driver /driver:%driver-main% /recurse
dism /Unmount-Wim /MountDir:%mnt% /commit
dism /Mount-Wim /WimFile:%src%\install.wim /index:2 /MountDir:%mnt%
Dism /image:%mnt% /Add-Driver /driver:%driver-main% /recurse
dism /Unmount-Wim /MountDir:%mnt% /commit
dism /Mount-Wim /WimFile:%src%\install.wim /index:1 /MountDir:%mnt%
Dism /image:%mnt% /Add-Driver /driver:%driver-main% /recurse
dism /Unmount-Wim /MountDir:%mnt% /commit
echo .........................................
echo Driver integration complete
pause
exit
And for post install options, I use the %cdrom%\sources\$oem$\$$\Setup\scripts\setupcomplete.cmd method (thanks to Ricktendo64 for the .net4 ideas), but I'll be transitioning some of the below to a custom WPIW installer session later.
setupcomplete.cmd for Win7
@echo off
for %%i in (C D E F G H I J K L M N O P Q R S T U V W X Y Z) do if exist %%i:\sources\install.wim set CDROM=%%i:
echo Found CD-Rom as drive %CDROM%
::Begin hotfix install
:Malicious software removal tool
echo Installing Malicious Software Removal Tool
IF EXIST %SystemRoot%\SysWOW64 start /wait %CDROM%\updates\windows-kb890830-x64-v3.22.exe /Q
IF NOT EXIST %SystemRoot%\SysWOW64 start /wait %CDROM%\updates\windows-kb890830-v3.22.exe /Q
:Defender Definitions
echo Installing Windows Defender Definition updates
IF EXIST %SystemRoot%\SysWOW64 start /wait %CDROM%\updates\WinDefUpdate\mpas-fe64.exe /Q
IF NOT EXIST %SystemRoot%\SysWOW64 start /wait %CDROM%\updates\WinDefUpdate\mpas-fe.exe /Q
:DirectX
echo Updating DirectX
start /wait %CDROM%\updates\directx\DXSETUP /silent
:NET Framework 4
echo Installing .NET 4 Framework
::start /wait Client\netfx_core_x64.msi EXTUI=1
::start /wait Extended\netfx_extended_x64.msi EXTUI=1
start /wait %CDROM%\updates\dotNetFx40_Full_x86_x64.exe /passive /norestart
IF EXIST %SystemRoot%\SysWOW64 start /wait %CDROM%\updates\NDP40-KB2160841-x64.exe /passive /norestart
IF EXIST %SystemRoot%\SysWOW64 start /wait %CDROM%\updates\NDP40-KB2416472-x64.exe /passive /norestart
IF EXIST %SystemRoot%\SysWOW64 start /wait %CDROM%\updates\NDP40-KB2446708-x64.exe /passive /norestart
IF EXIST %SystemRoot%\SysWOW64 start /wait %CDROM%\updates\NDP40-KB2468871-v2-x64.exe /passive /norestart
IF EXIST %SystemRoot%\SysWOW64 start /wait %CDROM%\updates\NDP40-KB2478663-x64.exe /passive /norestart
IF EXIST %SystemRoot%\SysWOW64 start /wait %CDROM%\updates\NDP40-KB2487367-x64.exe /passive /norestart
IF EXIST %SystemRoot%\SysWOW64 start /wait %CDROM%\updates\NDP40-KB2518870-x64.exe /passive /norestart
IF EXIST %SystemRoot%\SysWOW64 start /wait %CDROM%\updates\NDP40-KB2533523-x64.exe /passive /norestart
IF EXIST %SystemRoot%\SysWOW64 start /wait %CDROM%\updates\NDP40-KB2539636-x64.exe /passive /norestart
IF NOT EXIST %SystemRoot%\SysWOW64 start /wait %CDROM%\updates\NDP40-KB2416472-x86.exe /passive /norestart
IF NOT EXIST %SystemRoot%\SysWOW64 start /wait %CDROM%\updates\NDP40-KB2446708-x86.exe /passive /norestart
IF NOT EXIST %SystemRoot%\SysWOW64 start /wait %CDROM%\updates\NDP40-KB2468871-v2-x86.exe /passive /norestart
IF NOT EXIST %SystemRoot%\SysWOW64 start /wait %CDROM%\updates\NDP40-KB2478663-x86.exe /passive /norestart
IF NOT EXIST %SystemRoot%\SysWOW64 start /wait %CDROM%\updates\NDP40-KB2487367-x86.exe /passive /norestart
IF NOT EXIST %SystemRoot%\SysWOW64 start /wait %CDROM%\updates\NDP40-KB2518870-x86.exe /passive /norestart
IF NOT EXIST %SystemRoot%\SysWOW64 start /wait %CDROM%\updates\NDP40-KB2533523-x86.exe /passive /norestart
IF NOT EXIST %SystemRoot%\SysWOW64 start /wait %CDROM%\updates\NDP40-KB2539636-x86.exe /passive /norestart
:options
::Requires .NET 4
echo Installing Super Calendar
IF EXIST %SystemRoot%\SysWOW64 start /wait %CDROM%\updates\WinCal-Win7-amd64-en-us.exe /S /v/qb
IF NOT EXIST %SystemRoot%\SysWOW64 start /wait %CDROM%\updates\WinCal-Win7-x86-en-us.exe /S /v/qb
echo Installing Pinball
start /wait %CDROM%\updates\WinPinball-en-us.exe /S /v/qb
:WPIW
::Begin WPIW
echo Starting Windows Post-Install Wizard
REG ADD "HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main" /V "Disable Script Debugger" /T "REG_SZ" /D "no" /F
REG ADD "HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main" /V "DisableScriptDebuggerIE" /T "REG_SZ" /D "no" /F
::Start %CDROM%\WPI\wpi.exe
::all processing finished, delete used files, and EXIT::
:CLEANUP
start /wait %windir%\Microsoft.NET\Framework\v4.0.30319\ngen executequeueditems
IF EXIST %SystemRoot%\SysWOW64 start /wait %windir%\Microsoft.NET\Framework64\v4.0.30319\ngen executequeueditems
IF EXIST %windir%\Setup\scripts RD /S /Q %windir%\Setup\scripts >nul
DEL /F /Q %0% >nul
exit
And for you testing types, here's some experimental code for all NT6 OS (auto adjusts). Code in-work.
@echo off
:: Do NOT use trailing backslash in paths (i.e. C:\mnt instead of C:\mnt\ )
:: Hardcoded paths (C:\etc) are acceptable, but discouraged in favor of flexible relative paths
:: such as (%~dp0\ "the directory containing this script", or %cd% "current directory", or ..\..\ "back two directories")
:: Network shares (\\server\path) are not supported by this script.
::Set Paths to directories here.
:Path to mount folder
set "mnt=%~dp0mount"
:Path to temp folder
set "tmp=%~dp0temp"
:Path to source .wim files
set "src=%~dp0source"
:Path to driver folders (each should contain x86 & x64 folders)
set "driver-boot=%~dp0Drivers\Boot"
set "driver-main=%~dp0Drivers\Install"
::Do NOT modify anything below this line unless you know what you are doing!
:Environment checks
:DISM-check
IF NOT EXIST "%WINDIR%\SYSTEM32\DISM\DISMHOST.EXE" GOTO ERROR1
:WIM-check
IF NOT EXIST "%src%\*.wim" GOTO ERROR2
:Driver-check
IF NOT EXIST "%driver-boot%\*" GOTO ERROR3
:Index-start
set idx=1
:Index stop
set bootx=2
dism /get-wiminfo /wimfile:"%src%\install.wim" > "%tmp%\index.log"
dism /get-wiminfo /wimfile:"%src%\install.wim" /index:1 > "%tmp%\detail.log"
setlocal EnableDelayedExpansion
set "cmd=findstr /R /N "^^" "%tmp%\index.log" | find /C "Index""
for /f %%a in ('!cmd!') do set indexs=%%a
cls
echo %indexs% Install.wim indexes found.
:Arch detection
if exist "%tmp%\detail.log" (
FOR /F "tokens=* skip=2 usebackq" %%a IN (`FIND "Architecture" "%tmp%\detail.log"`) DO (
set str=%%a
for /f "tokens=2 delims=: " %%b in ('echo !str!') do (
set arch=%%b
))
)
echo The install.wim architecture is %arch%
echo Using boot drivers from folder:%driver-boot%\%arch%
echo Using main drivers from folder:%driver-main%\%arch%
:begin-boot
echo Integrating Boot WIM Index: %idx%
Dism /Mount-Wim /WimFile:"%src%\BOOT.WIM" /index:%idx% /MountDir:"%mnt%"
Dism /image:"%mnt%" /Add-Driver /driver:"%driver-boot%\%arch%" /recurse /forceunsigned
Dism /Unmount-Wim /MountDir:"%mnt%" /commit
if "%idx%"=="%bootx%" set idx=1 & goto begin-install
set /a idx+=1
goto begin-boot
:begin-install
echo Integrating Install WIM Index: %idx%
Dism /Mount-Wim /WimFile:"%src%\install.WIM" /index:%idx% /MountDir:"%mnt%"
Dism /image:"%mnt%" /Add-Driver /driver:"%driver-main%\%arch%" /recurse /forceunsigned
dism /Unmount-Wim /MountDir:"%mnt%" /commit
if "%idx%"=="%indexs%" goto END
set /a idx+=1
goto begin-install
:End
echo .........................................
echo Driver integration complete.
:Cleanup
cd %SYSTEMDRIVE%\
IF EXIST "%tmp%\*" DEL /F /S /Q "%tmp%\*" >nul
echo Cleanup complete.
:Exit
pause
exit
:ERROR1
IF EXIST "%WINDIR%\SYSWOW64\DISM\DISMHOST.EXE" GOTO WIM-check
ECHO DISM utility not found. Please install the Microsoft WAIK suite of utilities.
echo Windows® Automated Installation Kit (AIK) downloads
echo WAIK 3.0: http://www.microsoft.com/download/en/details.aspx?id=5753
echo WAIK 3.1 supplement: http://www.microsoft.com/download/en/details.aspx?id=5188
goto Exit
:ERROR2
IF EXIST "%src%\sources\*.wim" set "src=%src%\sources" & GOTO Driver-check
ECHO WIM files not detected. Please check source directory.
goto Exit
:ERROR3
IF EXIST "%driver-main%\*" GOTO Index-start
ECHO Driver files not detected. Please check driver directory.
goto Exit