I was originally going to suggest this for V12, because it'd be a killer.
I've called it Multiroll rather than Multicam just so no one gets confused and I think that's what Avid calls it and charges a bomb for on their high end systems.
Difference is you have one preview monitor per source, and one for the output. Not knocking what the various script solutions offer, it works very nicely for the money but I cannot see a director type putting up with watching tally lights jump around quadrants.
Just think it'd be nice for Vegas to come out with something really startlingly new that no one else (except maybe Newtek?) have to offer.
Bob.
Edit: Didn't realise someone already had 002!