If you haven't checked out Cameesa then, well... you should. Cameesa is a crowdfunding site for artists to get their shirts printed and supported at the same time.
Essentially, you can support designs at $10 a shirt + shipping, and when there is enough support for a design the shirt will print and you'll receive a shirt for every $10 you pledged and the artist will receive $250 bucks. There needs to be 50 x $10 ($500 total) for a design to go to print.