Hmmm...awesome idea.
I'm not sure if this will help or not, Here's something I whipped up in Fireworks...not sure if you'll like it. I'd suggest keeping it simple (as in, not Photoshop from here to Kingdom Come) because if you ever want it printed on shirts/mugs/anything else, most places will want vector files (like Illustrator, Fireworks, etc. and usually not Photoshop) with as few vector points as possible. Colors aren't an issue, but the less colors = the less $$$ you'll spend on printing.
This is one color, but I/you can color it up however you want.
--J