No need to powder coat it Steve. Hell, powder coating would just melt the cover down...
All you need is a good (and I mean GOOD) paint to do the job. I've custom painted my computer cases, laptops, and such with colors from House of Kolor ... beautiful paint, and it goes on soooooooo smooth with an airbrush.
There is, of course, colorwarepc.com too .. for people who like to throw money around.
-Martin