If you look at the list of BOLT ON DISC BRAKE donor cars, these cars will have a bolt in rear. The interchange is limited, so it's hard to bone because most of the crcaces have been picked clean.
This board is probaly as good of a bone picking area, as anyplace. I recall a bad deal between 2 board members, but I think that they finally got things straghtened out. Even so, from what I'v noticed, the parts/money swap usually nets 99.999& satisfaction, and there are lots of f/g/f members of whom I wouldn't give it a second thought about the worries of "mail order" deals.
Even with shipping, you might be better off dealing with f/g/f members because there is a lot to be said about 100% satisfaction. There are guys here who sell f/g/f parts on eBay, and they post, "Hey folks, I'm giving you first crack at whatever, and I want however much for it. If I don't get a bite, in x-days, it's going on eBay.
Where the hell else are you gonna' get such inside connection?