Actually, most of the newer Jeep Grand Cherokee's (sp) are powder coated and alot of higher end autos as well.

Bumpers and all plastics are usually still painted, but it is possible to powder coat other materials. I have seen kitchen cabinet doors made of wood that have been powder coated. All you need is a conductive primer and a low cure temperature, very flexable coating for plastics.

Its not a very good choice to redo a car and have it powder coated as the car would have to be totally disassembled so the metal could be pretreated.

To do your wheels or calipers or shift knobs, is one thing, but a Whole CAR, I wouldn't.