I just wanted to post an "atta boy" to the guys at Tamron/Bronica. I called them for a replacement back-to-body mating plate for one of my SQ-Ai backs and some metal foil darkslide seals. Despite a cellphone connection that dropped several times, they were wonderful to deal with and very helpful.
A lot of camera companies won't sell parts to J.Q. Public, so it was refreshing to be able to call - without knowing any of the part numbers - and have someone take the time to walk look the books, take the order, and get it shipped the same day.