No time for a full write-up, but LifeHacker mentioned Sandboxie today and that led me to look at Altiris SVS. I've been espousing file system and registry virtualization in Vista quite a bit lately and this just kicks it up a bit.

When I get time (after my final) to play with this, I'll post a more complete review or see if SF is interested in a full feature. Meanwhile, grab the tools and give them a go!