Bruce,
I don't have any personal experience with painting the plastic parts...but that won't keep me quiet.
I've seen people paint up their KLR's, which are also full of plastic parts- I can look to see, but I think it's ABS (butylstyrene). Krylon makes some plastic-specific paints that stick to ABS; not sure about how long the finish lasts. The pictures I've seen don't look outstanding (usually its a matte black urban assault style paint job). Apparently, using a plastic-specific primer is essential. Normal rattle can paints and primers do not stick well to the plastic. Of course, for first quality finish and good color match, a professional paint shop can't be beat.