actually there has already been one
In one of the early UFC'c there was an Aikidoka who fought. Suposedly he was a Shodan. He got his A$$ kicked along with the rest of his sorry carcass. As a watcher and Fan of MMA events I would say that Some knowage of the tactical concepts of Aikido might be usful but that's about it. Judo (which is all BJJ is in the end), wrestling, boxing and Thaiboxing are infinatly more appropriate dicipline for MMA competitors to study.
That said Mixxed Martial Artist are artist in the same sense that an Aikidoka or a Judoka is they just have a differant Focus. Traditional/Koryu pracianers on the other hand are a bit differant. There art require everybit as much dedication as MMA but the flexible nature that is in MMA doesn't come into being until much later. This is in my opinion due to the transmission nature of Koryu arts. Which is not to say that the techniques aren't useful either just that the Focus isn't the same. I have trained with MMA people and they take their art serious. Class starts with a warmup that would have many so called martial artist puking 500 squats countless crunches and pushups and other conditioning exercises (I say countless because I did lose count after 100 and I did puke). After all that they work technique just like anyother school slow first and then speeding up. It was rather like judo in shorts and a rashguard instead of a gi.
True modern man to man combat would be better reflected in the art of "Shotgundo"(TM) than in any weaponless art