I've run powder coated rims on a variety of bikes with no problems BUT for a low cost alternative you might want to try spraycan epoxy. I have used black epoxy appliance paint (anyone ever see a black refrigerator??!! Not me, but that's what the can says ) on rims, oiltanks, handle bars, gas tanks, just about anything not subject to high heat.
Costs about $5 at Home Depot or most hardware stores.
Bead or sand blast to remove rust or loose chrome. Don't use primer, just epoxy on bare metal.
Spray lightly and keep going over the whole piece until you've got good coverage. Avoid runs, it's a pain to sand and hard to second coat unless it dries for quite a long time. Dries to a hard ,glossy finish.
Try it on some junk part first to see the result, just so you will know what you're getting .
I've got a '49 Harley that I built on a budget. Had the front rim powdercoated gloss black but painted the less visable rear rim with epoxy. Rear is slightly less glossy but no one has ever noticed but me.
