A Pentax 6x7/67/67II with a 105mm f/2.4 would be similar to a 50mm f/1.1 (roughly), I've recently just got my P67 kit together and love the size over smaller 35mm cameras. I have big hands so an EOS 3 + grip is more comfortable than just the body.

You might want to look at the FD 50mm f/1.2L or Asph with an F1/A1/AE1 if you stick with 35mm as the f/1.2 lenses are much cheaper in manual focus.