You might try http://www.livefishforpondstocking.com. They don't list shiners on the site but basically it just some guys with a fish truck who act as a middle man for some fish farms. They are based in Smithton so they are very close and you might be able to work something out with them. I have never bought fish from them but just spoke briefly to one of them on the phone.

Does the name Pavlov ring a bell?