...I also agree with this approach, talking with the guy 'man to man' outside the dojo over a beer. My guess from what little you've said is that this guy just has no respect for you at all, and this meeting will at least start him thinking that maybe he's made the wrong assumption about you. He might not even be aware that he's been such a jerk toward you, and this will at least bring that to his attention. If he refuses or continues to treat you disrespectfully during/after your talk, then the guy is just an arrogant jerk, and there's nothing you can do about it.
...but where I differ from Ron's opinion is that I would NOT leave the dojo! Continue to train, just ignore this idiot! And don't 'fight' this guy, that's just plain wrong! [A fight won't decide who is right, it just decides who is stronger!!! ...not very Aiki!]
...by doing the beer thing, you've done all you can to fix the problem, but sometimes problems just can't be fixed ...and life goes on! ...BUT DON'T QUIT!!!!!
Easier said than done. If hes doing it now he is going to continue doing it. And from the looks of it, he is going to be allowed to do it. Can't tell from the size of the class, but I think it will be kinda hard to avoid him. Its a direct blueprint of what goes on during bullying in elementary school. The guy even wanted to fight him for no reason. If he stays, I think a fight will ensue sooner or later. Better see how your sensei reacts too, last time i checked it was aikido not a underground bar fighting karate.