So, I don’t have access to a test farm of physical computers. But I do have Windows 8 x64. (This will also work on Win7-x64). Add the Hyper-V role in ‘Control Panel > Programs & Features > Turn Windows Features On/Off’ and you can create a virtual test farm right on your PC in the form of Virtual PCs.
One problem I came across when testing my answer file was that I couldn’t get the Hyper-V to recognize USB/UFD devices so the answer file was not being read.
The solution: Create a VFD (Virtual Floppy Disk). Mount it into another VM (that has windows already installed) and copy the answer file into that. Eject the VFD and mount into your VM that you will be installing Windows onto. When you run the windows install, the answer file will be read..Happy Days!
NOTE: This will not work on x86 architecture. You can add the Hyper-V role and manage other Hyper-V servers but can’t create new VMs.