I tried to just extract the N3 directory, rename the N3 folder name to files, put that into the 3rd party section and rebuild with the below entries in the 3rd party inf file:
[WinntDirectories]
a=nview,1
[SourceDisksFiles]
files\nvdm.inf=20,,1
files\advanced.tvp=a,,1
files\default.tvp=a,,1
files\nvsvc32.exe=2,,1
files\keystone.exe=2,,1
files\nvappbar.exe=2,,1
files\nvapps.xml=2,,1
files\nvdspsch.exe=2,,1
files\nview.dll=2,,1
files\nvshell.dll=2,,1
files\nvtuicpl.cpl=2,,1
files\nvcpl.dll=2,,1
files\nvcpl.cpl=2,,1
files\nvwimg.dll=2,,1
files\nwiz.exe=2,,1
files\nvhotkey.dll=2,,1
files\nvmctray.dll=2,,1
files\nvshell.dll=2,,1
; begin Locale
files\nvmccs.dll=2,,4
files\nvmccssr.dll=2,,4
files\nvdispsr.dll=2,,4
files\nvgamesr.dll=2,,4
files\nvmoblsr.dll=2,,4
files\nvvitvsr.dll=2,,4
files\nvwssr.dll=2,,4
; end Locale
files\nv4_disp.dll=2,,1
files\nvcuda.dll=2,,1
files\nvdisps.dll=2,,1
files\nvmccss.dll=2,,1
files\nvmobls.dll=2,,1
files\nvvitvs.dll=2,,1
files\nvwddi.dll=2,,1
files\nvwss.dll=2,,1
files\nvcod.dll=2,,1
files\nv4_mini.sys=4,,1
files\nvoglnt.dll=2,,1
files\nvwdmcpl.dll=2,,1
files\nvmctray.dll=2,,1
files\nvwddi.dll=2,,1
files\nvcpluir.dll=2,,1
files\nvgames.dll=2,,1
files\nvexpbar.dll=2,,1
files\nvcpl.hlp=21,,1
files\nvwcplen.hlp=21,,1
But it does the same thing as my own saying nv4_disp.dll failed to load. It has the correct name entry, so it does see it, like my own. I assume it fails for the reason you specified previously. Be nice if there was some log file to view which gave a bit more specifics then the little event viewer entry in winpe. Which of course is about 0 help to you I know. I'm guessing the building of the driver base for UBCD4win skips many of the included driverpack entries for stablity reasons since this is a PE build. But again only guessing. Thanks for trying anyhow. Hope something comes about, otherwise I'll just keep hackin' away at it til I finally pop a blood vessel or something.
Maybe because I'm not including the security catalag (.cat) file? Hmm...have to try again. Frisbee time again!