I got some AP racing calipers for my car powder coated. Got them done by a place in Sydney called Craved Coatings. Result was exceptional. I gave them some AP racing stickers to use as a stencil then they coated them white (so the logo would be in white), applied the stickers then coated them silver (to give the colour more depth) then gold, removed the stickers and coated them with several coats of clear. I'm sure they could do a set of wheels no problem. They also do all kinds of crazy colours like metallics and candys.
Done a few thousand kms now and even with the obvious heat from braking (quite hard) they haven't discoloured at all.