In reply to adamholden:
Endura make our club kit (formerly Castelli), but I suspect you would be right on the min order front - might be worth asking, as they're a UK company.
Otherwise, I would buy some plain kit, ideally end of line/sale stuff (obviously!), and then take it to a company that prints t-shirts - depends how detailed you need it to be. Had a small run of about 7 jerseys done that way as unofficial kit for another club. Check with the printers what materials they can deal with first, though.