This is the gift that keeps on giving: I got my friend a Star Wars Bowcaster for his birthday, and have since painted it up and am giving it to him again for Christmas!
Since it was brand spanking new out-of-the-box, I started by roughening it up a bit - I used a technique I like to call 'dropping it onto a pebble beach and kicking the ****** out of it' - to add a bit of battle-wear, and then a matt black base-coat. Chewbacca's actual Bowcaster is a pretty boring affair, as it's plain black with a few scratches and that's about it... I decided to give it a little more personality, and so I decided to go with a wooden stock and some brighter metal parts for the knobs and dials.
I also held off giving it my normal coat of dirt at the end, as the worn-but-clean look is kind of appealing, but I'll give him the option if he wants it later on...
http://i.imgur.com/gHmjnWT.jpg
http://i.imgur.com/vh2wxyM.jpg
http://i.imgur.com/rJu2Vrc.jpg
P.S. If you're thinking of getting one of these to mod, whatever you do, DON'T attach the bow to the body when you take it out of the box. It clicks into place and locks the blaster shut, effectively stopping you from ever being able to open it up to get at the internals.