Pretty cool idea.
It saves the embarrassment of begging GM's to watch videos of you working out in your driveway, TO.
Definitely might help with some guys who were never even on the GM's radar, someone maybe written off showing he can still move, etc. Given how short NFL careers are on the average I think players would be nuts to turn down any opportunity to show they can still perform athletically.
Edit: Do we get a guy like Andre Carter in 2011 if he had a chance to show how much of a workout warrior he was? Or rather, do we get him basically for free with that combine idea in place? Players obviously work out for a team before they sign but they rarely work out for all 32.
^and I just worried myself with that though. BB tends to be good at finding hidden gems under rocks that other GM's ignored.