hi peter,
you cannot sysprep a image that has been upgraded from one version to another or from one edition to another.
NewSID can run on a windows 2008 image but the outcome might not be really helpful. And incase of systems that are upgraded the same corrupts the image and results in bluescreen.
Though there are lot of articles to fix BSOD errors the same may not be very helpful in case of images that have BSOD during sysprep.
The best way left is to have a fresh OS template created for multiple deployments
regards
bhanu