I've used InfinitiCam on a couple of projects and it works great, paid for itself on the first job so I'm being my usual curmudgeon here.
This is nothing like real multiroll editing!
By that I mean say 4 tracks, each with its own preview monitor / tally and one for the mixed output.
Of course for this to happen (or even to come close) it'd have to be done inside of Vegas instead of using scripts to automate Vegas. Probably need to start treating video like it does audio with track / buss routing to multiple outputs.
Bob.