This is basically a duplicate of this question, but the accepted answer was \"no\" and I would like to keep this question open until getting an actual answer instead of acceptin
It look like it may be possible to automate the creation of virtual images using MS Virtual Server 2005. The following articles detail the use of PowerShell scripts to automate the creation of virtual images:
From part 2, in the section Configuration Tests on a Virtual Machine, it seems possible to transfer files and schedule scripts to run. Using these articles as a basis, it should be possible to automate the building of a MS virtual image in the same way as lordbrain described for a VMware image.