I know a local shop that will do any color for any part any anytime. They do great work. I think 17" wheels start around $75 each. Most shops I looked at were aroudn that ball park price too.
As far as color, PC can do anything from a flat color to what looks like chrome. A buddy of mine's STi had a purple chrome that looked great with his black car. Personally, I like the idea of black chrome on the GTO... especially if you get your exhaust tips to match and black the rest of the car out.
2003 Corvette Z06 - MGW shifter, Corsa X pipe, Corsa Xtreme exhaust, Texas Speed long tubes w/o cats, PowerStop rotors/pads, Conti DWS tires, C6Z51 F&R sways, C5R headlights, tuned
04 GTO - sold