Chris,

We've always bought our own stock of whatever we're going to have printed or screen printed and then just supplied them to the printer. That way, we usually save a little money and end up with a better product, because as you said, most of the stuff the screen printers buy from their wholesalers is crappy quality. As for color on underwear, when we did our blue and purple underwear, we just bought white and dyed it.

As for printing, there's a really inexpensive screen printer in Oakland I can get you info for if you need it. They also do embroidery but I haven't used them for that.