I would think the only reason people don't do a single carb setup is that most don't have the ability to fabricate an intake manifold for a single carb.
it came to me this morning at work...
gonna have to do a 1 to 2 to 4 setup, and keep the runners fairly even in length, otherwise you're gonna have two rich holes and two lean holes..
remember those Offenhauser dual-plane intakes for the 351 Cleveland?