Art + plexi would probably be the easiest way, but unfortunately your T-molding will no longer cover the entire side... the height of the plexi will be above the T-molding's edge.
Or just have the art printed on adhesive backed vinyl. Remove the controls, stick the art down, cut holes, replace parts..... done. You shouldn't have a problem with T-molding so much with this option since the vinyl will be relatively thin.