If it's just powdercoating, ESP are pretty good and reasonably priced. They do car and bike wheels and are currently based in Port Dundas though I think they are about to move. I can get their number if you're keen, they are also in the Yellow Pages.
Contact Trevor at ESP 0141 336 3800 tell him I sent you (that's possil not Port Dundas) and he has not moved yet...in the new year I think...He does a same day service top top fella