I just started with MDT2012 recently in hopes of eventually getting away with using Ghost to deploy all of our department computers. When I test deploy in VirtualBox, it deploys the OS properly, but stops because of a network driver failure (it gets the "could not allocate resources" issue).
On physical hardware (Latitude E6500, Optiplex 980, and an older Latitude) it gets through the multicast and stops immediately after with:
"Setup was unable to create a new system partition or locate an existing system partition. See the Setup log files for more information"
I've looked at the logs and never see anything really of note. Originally I was using DriverPacks from DriverPacks.net, but thinking it was a driver issue, I switched over to using Dell's cab driver packs. Still the same issue.
I check and it did the HDD is all fine - it was properly partitioned, set to bootable, and was loaded with all the proper OS installer files.
I'm using a flash drive to do the install - when I make changes to the deployment share I rebuild and copy the ISO to the drive, then use YUMI multiboot to start the ISO (probably irrelevant).
As I suspected in my comment, the problem IS related to booting from the flash drive. I looked around and saw a few people who had recommended this for older editions of WDT. I initially dismissed the solution, assuming it to be a RAID configuration on the 980, but it does seem to be the case. The LiteTouch***.iso which WDT provides should be burned to a CD or mounted directly - attempting to boot the image from an external drive seems to cause some confusion in the Task Sequence when it begins to launch the actual installer