I bought the Datsun 210 five speed tranny last year, and felt guilty for paying $425. Its amazing how the prices have gone up! I followed that one on ebay for $830+. I was not feeling too guilty about my purchase then! There must be thousands of old Datsun 210's in scrap yards still remaining. I read an article last year where a person could even go to an auto scrap yard and ask to see all of their shelved transmissions. The 210 would be the smaller ones, and look for all of the appropriate markings as listed on the Rivergate web site, the author of the article was probably right in saying how after 20-35 years, even the car wreckeryard people dont know what is in there storage areas.
Incidently, I bought mine from one of the recommended sellers on the Rivergate site. The guy (California) doesn't sell on ebay, he just waits for someone to call. He had two when I called him, and the ebay auctions were above $500 at that time.