does anyone know of a butcher in brooklyn or manhattan that regularly sell raw sweetbreads
HMMM... Well, most of them do I would suspect, any of them would get them to you in a days notice.. But, ones off the top of my head where i would regularly get them- Eataly, Citarella, and Ottomanelli.. i know Paesanos in BK has them frozen but, again, just ask and give them a day.
But, really any butcher should be able to get you any cut of meat. Just talk with them.
Paisanos Meat Market
162 Smith St, Brooklyn, NY 11201