Hey SS, what did you end up doing for this build? Only easy way I can think of is having your multicolored LED's behind a glass / plastic / frosted window with a white backdrop or something similar just to give the appearance of the "paint" changing..
I've actually just started working on this again and was thinking just going with high gloss black or white paint and making covers for everywhere I want to light up. I'll get on it more near the end of the month and keep you posted.
How have you been and how is the visual design work going ? really loved some of your photoshop work you posted a year back or so would love to see anything new you got