I was actually reading these tweets while they were happening when I was at work. I thought it was pure comedy gold. Chad mentioned that he wanted to do it for a charity and that they could make a lot of money for a good cause.
I'd like to see it, Johnson is a pretty big dude. Isn't he about 6'1" and 200 pounds walking around? He's an athletic dude and he's got charisma, if he decided to make the transition to MMA for real I would expect him to be a pretty good fighter and a good draw at the very least.