FYI, I copied this from another forum (photo.net), unverified....
October 17, 2005
October 14, 2005, Commack, New York Tamron USA, Inc. announced today that it has discontinued the production of the Bronica RF645 6x4.5 range finder camera model along with its relevant interchangeable lenses and accessories. The discontinuation of this last Bronica model marks the termination of the Bronica brand business. Bronica withdraws from the medium format camera business after 47 years since its first model, the Zenza Bronica D, was introduced in 1959.