Why T-shirts? Something I can believe in. Graphic activism. Not works of art that go over rich people's couches, but made for the people. And hey, it can be by the people, too. Send me your art. If I like it, I'll offer it, with your name on it and share profits. Let me know...
And—with t-shirts, everyone wears them. When they get old, you can wear them to bed. When they get really old you can use them as rags and eventually throw them away. They'll be completely gone from the landfill in just a few years.