aerosol "plasti dip" is currently very popular. search the internet...its kinda amazing.
some random web site wrote:Plasti Dip is a multi-purpose specialty rubber coating that can be easily applied by spraying. PlastiDip protective coating products resist moisture, acids, abrasion, corrosion, skidding/slipping, and provides a comfortable, controlled grip. It remains flexible, stretchy and will not become brittle or crack in extreme weather conditions. Perfect for spraying badges, wheels, etc. If you decide to change the look of your Plasti Dipped items, cured Plasti Dip will peel off easily from most surfaces. It leaves the material underneath in its original, pre-dipped condition.
i have not done this myself but an acquaintance of mine sprayed his (honda blackbird) wheels with good results. i think he bought his stuff at dipyourcar.com