several people on this board have painted their gray plastic black, but i dont think its the type of paint job your talking about. i'm talking about a spray paint can with flat black or semi-gloss. i'm sure you talking about paint the way the sheet metal on a vehicle is painted. only problem with that is, if you ever bend that plastic peice, i am sure that he paint would not be as flexible as the plastic and would probably crack off.
then again, there is "daggerdoggie", his method of madness is quite unique.