Well, thanks for your input, OverFlow... Though it doesn't help me with the issue i have, it's interesting.
I think i get it : "you hate sysprep". Ok. But how to achieve the same without it ?
Lookint at your post (#51 of the present thread), i see you recommend to make an Unattended Windows XP CD, with slipstreamed patches and drivers (nLite / RVM).
My matter is, i'm using localized (french) version of Windows XP, so i can't use RVM (please correct me if i'm wrong on this). Finding out what patches i need to make a clean and fully updated UWXP CD is a task i don't have the time for (maybe i'm wrong on this point and it would be far easier than i think)
I also didn't catch the point : how and when do you install/configure all the software you want to be on your duplicated computers ? I think it's during the WPI phase, but can you confirm me that EVERY software will make it ? To be more precise, here are the softwares i usually install : 7-zip, Adobe Reader, Audacity, CDBurnerXP, CDEx, Mozilla Firefox / Thunderbird / Sunbird, Adobe Flash & Shockwave plug-ins, QT Lie, Real Alternative Lite, Media Filters Pack, PhotoFiltre, Gilp, Google Earth, Stelarium, Java, JkDefrag, OpenOffice and its (french) dictionnaries, , MS PowerPoint Viewer, Scribus, UndeletePlus, Skype, Windows Live Messenger, SuperCopier, The KMPlayer, utorrent, WinAmp & XnView.
About the time costs : if i can make the sysprep way to operate, i think i can have a ready-to-operate new unit in less than an hour, all included - duplicate partitions with ntfsclone, chkdsk 'em, put the HDD in the case, switch on the device and making all the not automated things manually (for an example, i set a toolbar in the system Windows bar, which is a "link" to a folder on the user's desktop : for now, i didn't find the way to automate the creation of this toolbar... ?).
It may be twice (or more) the time you need, but it already vould be far better than the present situation (installing everything from sractch takes me something like 5 to 6 hours per unit). OK, that's no good reason to keep using sysprep.
Please forgive my logorrhea, i may be a little over-exhausted... Thanks for your attention, though !