I am in the same boat as smahar. I chose to make a universal image for our campus (used the driverpacks guide here) along with mysysprep) and it worked as long as it didn't have to actually switch hals. On my first attempt I realized that I didn't copy the kernel or alternate hal to the system drive, though, so I just put up another quick-fix attempt and it still doesn't update the HAL at all. If anyone has it working can they post up which kernel should be put where and the hal that should be relocated, etc...
...If I can get mine to work I'll make a guide that covers the MySysprep step because it's a bitch+1 to go sifting through the forums to find what I'm looking for.