You can have this done and it's not too expensive if you find the right place or know someone. I work in a wheel manufacturing plant and we powdercoat about 80% of the wheels we make. There's three ways you can do it...1. clean and paint the rim, then have a clear powercoat put on top of the paint, 2. have a clear powdercoat put on then color on top of the powdercoat, then clear paint on top of the color (this is how most wheel manufacturers do it) or 3. some places have colored powdercoat (I've heard this is most expensive). As for powdering used rims, I wouldn't recommend it unless you can completley clean them of ALL grease and oil. Powder coating is very vulernable to grease and oils. The powder will swell up (look like little tiny zits all over the wheel) if there's any kind of contaminants on the wheel especially when it goes through the ovens. The ovens will heat up the grease and oils and produce vapors which will completley ruin your powdercoating job. Even with the degreasing and etching processes that our new wheels go through, we still get some wheels that don't turn out, I'd like to see what a used wheel would look like....I'd just paint em.