OK, two mentions of my name in one thread and I have to pop up like the proverbial genie -though why, I'm not sure... . I have some small (positive) experience with New England Photo, in Arlington, MA and I know that
E.P.Levine, in Boston has some great used equipment - Mike might be the best guy to speak with there, not sure. They always have great stuff cheap at the PHSNE Photographica show.
I get all of my gear through a friend, Dick Welch, at Assabet Valley Camera, in Maynard, MA. He has no store, however, and trying to get anything on short notice or browse his inventory is not really possible. Were you looking for something in particular, Tjaded? Dick is the source of all those filters and adapters I've been giving away.