Well it might look too trendy, but if you could somehow print/paint japanese or chinese characters along the bottom of the CP in black, that might actually not look too bad.
If you're thinking more along the lines of CP overlays, one big issue is that you usually gotta have a layer of plexi/lexan over the overlay so it doesn't basically get ripped up after hours of usage. This lowers the amount of space that you have to move around the joystick, which can definitely hinder play, so sometimes just sticking with a very nice coat of polyurethane over a coat of paint is the best way to go. It involves the least hassle, that's for sure.
-Luke