Reptile Shops:
Pets Plus in Tewksbury MA was selling live rodents as feeders (last time I was there - a year ago).
Dinky Reptiles in Auburn MA might have live feeders-I would call ahead. Phrased Politely: I'm not a fan of this store or the owner though.

Prey Breeders:
There are a bunch, if you post in the Pet section of Craigslist that you want to buy live feeders I'm sure you will get some contacts. One woman sent me a picture of 3 standup freezers full of frozen mice/rats/gerbils in her basement-I think she was located in Worcester somewhere...She said she could get me 'any quantity' of live/frozen---I think her prices were a bit high though...