Although sounding like an entertaining idea...
This would be one of the absolute worst things any reputable MMA organization can ever imagine considering. The reason why the Tag Team idea works in Pro Wrestling is because Pro Wrestling as a whole is worked. No one is in there without some sort of co-operative understanding of each other. All this takes is one unfortunate fall, an extended period of 2-on-1 and someone is going to get hurt badly.
If you thought the Boxing supremists had something to bitch about before, just one of these matches would prove all of their "barfighting/non-sport" touting soliloquies correct.
It doesn't matter if you agree or disagree
... As long as I don't bore you and I spark a moment of thought, my goal is achieved
Queng leon queng tigre ecu tacacut, queca pa? - Pampangan Mandarigma Motto