if the bb can protect their head then i wouldnt be surprised to see the bb ko a ufc guy.
the problem with this thread is that all you are comparing people from different weight classes.
i.e. penn and rampage etc against a would be 300lb muscular behemoth.
triangles, kimoras, rear nakeds and even guards would be very difficult to hold or even get against a 300lb BB who does 500lb+ benches. theyd break every attempt.
if you compare the heavyweight class then you're at least getting in the ballpark. some of those ufcers would press a mean bench and some are pretty large too.
on the other hand if you gave some of the pro BBs say, 6 months to get their cardio up and get some striking and defence tuteledge then you're comparing an all round lifting machine with an ability to have some stamina and some defence and attack.
its not just upper body strength in fight sports either...a punch is delivered from the feet upwards..so its the cumulative strength combined that goes into the fist.
you get a bb with a good chin or some boxing skills and personally i think you'd have someone who is very dangerous in the octagon.
the problem would be that bb'ers are there, in the first place because they want to be a thing of beauty, or have some ego that needs to be fed. that psychii doesnt lend itself well to teh prospect of being made more ugly or perhaps being defeated.
so the argument's probably moot for those 2 reasons alone.