It's a good idea. But I think it would be are too difficult to actually implement. But, it does definitely sound entertaining.
PS: Treyarch is making COD 5, and Infinity Ward is making 6. Both companies are part of Activision. Treyarch has 3 and 5 and will take the odds from now on. Infinity Ward has 1,2,4 and the evens from now on.