How would a Pro Bodybuilder do in MMA?

Molson,
You are making a silly statement.

An Oly wrestler would destroy a pro boxer?
Which wrestler and which boxer?

Have you ever seen Maywether or Vargas or Roy Jones fight? How about Tua or Ibeabuchi? These guys move way faster than any wrestler I have ever seen, and the big guys can knock out big men with one punch.

The sloppieness shown in MMA, even at the highest levels, would be exploited by a good boxer.

There are not any good boxers in MMA for the simple fact that even low level local fight cards pay more than all but a couple of top MMA fights. A .500 boxer who can get some fights on TV is gonna make 6 figures easy.