powder coat....
Powder coating is something I almost always advise against, due to the fact that any powder coating thats done right, subjects your parts to intense heat, this oven cooking process changes the molecular structure of the metal in your parts, making them brittle, and sometimes warp in the oven, rims that are aluminum will certainly suffer, same as an aluminum hub, steel parts are also weakened, (just not quite as much), the only hub I know of that would still be structuraly sound after this process would be the Staton hub as I've NEVER experienced a hub made of such tough material, (Took me all day to drill one with a carbide drillbit, regular bit's barely scratched it).
There are allot of different types of paint these days, and I'm pretty sure you could find a translucent paint that didn't require the Oven time, make sure you either sand blast or Glass bead or Wallnut shell the part beforehand so the paint won't just peel off, should work great !
Powder coat works fine for frames and some other applications, but for hubs and rims, I'm not a big fan of the Idea, Hope this helps..