I'd suggested it'd be great to have this kind of capability in Vegas and now damn it all Edirol have done it and in real time too:
http://www.edirol.com/products/info/cg8.html
Probably not something I'd use myself and obviously not real time in Vegas but given that the Edirol box will only load 48 still images the possibilites for doing this in a NLE would seem limitless and it could be in HD as well.
Bob.