I have never had to wear braces and I hope I never will.
Watgoplunk, why don't you learn flute? I know many flute players with braces, and nothing seems to be wrong with them.
My boyfriend got braces about a year and a bit ago, and at that time he played trumpet. It hurt too much, so he had to take up trombone, then he got them tightened, and it started hurting too much to play trombone.
On a brighter side, there are plenty of instruments out there that don't require embouchure. How about a string instrument like a harp, violin, or cello? Maybe percussion, maybe....ok, I'm out of ideas.
I will have to check all of the clarinet players next time I go to band practice, but I'm pretty sure that at least one of them would have braces. From what I know of playing clarinet (not much!) It shouldn't effect it too much.