I'm a little confused by this thread OP. Are you selling custom t-shirts for BTC (the design, creation or both?), or are you wishing to start a business & looking for a partner?
If you try to read it up carefully he do mention on those people who do wants to have a business where he would really act as a supplier of those t-shirts.
Making a deal or business with people online with less feedbacks wont really be that effective due to trust issues and further more for OP, could you post up some samples?