I like the idea of it, of course. As for dice, one of discussion topics I saw on the D&D proof of concept software project's own forums was about how to detect the results of dice thrown onto the Surface. Keep in mind that the Surface detects objects and actions via a single camera.
Apparently, most dice would be a bit too small for said camera's resolution to even see the results, but I think that maybe a custom-made die which has a different color on every side would work. Of course, that'd be a weird kind of die, but it'd
work, mostly.
In other, but related, news:
YouTube - Microsoft Mobile Surface