Classic VM-68 urban tiger stripe has always been one of my favorites.
With an opportunity like this it's hard to resist going nuts and doing something totally original though. I've always been fond of the dripping blood look as well ... black with red drops. I've never seen it in an anno though. Would it be possible to make the blood look 3D with some brushed white "reflection" accents? Like the classic 3 color random Eclipse splash kits of the 90's, except this time it won't be random, you'll be doing it deliberately and in the orientation the parts are going on the gun. That would just scream custom. Hell, put a bloody hand print on the pump handle. That would be too cool.
If your glasses fog up and you want to make your own mask fans, here's how;
"My happiness doesn't depend on anything. My heart is always happy. I do have anger issues though."