I know a custom Paint job for a toy gun ain't exactly art - but any kind of photography is - ha! gotcha.
Here's my custom painted MP7 (Well R4, actually, a quite cheap, popular Clone of the japanese Model from Tokyo Marui) in tan.
Why tan? Because I recently got a FN SCAR in tan. Since they have a similar "feel" due to all those rails and lots of plastic, I thought It'd look cool.
Paint job done disassembled, Metal Parts were thoroughly treated with paint remover (the cheap chinese paint job was quite awful and came off easily).
I used acrylic "gun paint" spray cans, which smell like a toxic hell and make you all woozy, but are worth the effort. The finish is superb and, at least on the metal parts, quite scratchproof.