I also had the same problem, but seemed to have fixed it using Windows Repair. Granted I had to run it twice. The first time Windows setup/repair tried to repair it automatically, but it still wouldn't boot. Then I ran the repair again manually (purposely selecting Repair My Computer, then selecting the detected Windows 7 installation, then selecting Startup Repair). Once the system rebooted, it went into its detecting drivers (system was sysprep'ed) and booted normally after that.
Have you tried restoring an image to any of the 200 systems you're deploying? I'm just wondering if the image being deployed is going to also have this issue. I have not deployed out my image yet as I am working on implementing HII, but don't want to introduce any more issues until this is resolved. Guess that'll be an update on this post when we figure that out.