How do I find Contax 645?
I also have M9 + Zeiss ZM 25MM + SUMMICRON 50MM, + ELMARIT-M 90MM + ELMAR 135MM. If I compare M9 set with the Contax 645, ignore the weight and portability, the obvious win is Contax 645's gradation.
I also have Hasselblad V and a similar set of lenses, ignore the convenience again (but this time Contax is the winner though), Contax 645 wins the micro contrast.
I also have Kodak SLR/C with a set of Canon L lenses, again ignore the weight and convenience, well, nothing the Kodak/Canon-L can be even close.
I've tried Nikon 800E and Canon 5DIII. I think those two win hands down in the tele-lens range, but the gradation is nowhere close to M9, not to mention Contax 645.
The bottom line, size does matter. If anyone try to convince you otherwise, use your comment sense. The difference between the MF 645 and the FF 35mm is similar to the difference between the FF 35mm to APS-C, or APS-C to M43, or M43 to Nikon 1, or Nikon 1 to Dlux-4. If you are convinced that FF 35mm makes more sense than MF 645, than you should ask yourself if a APS-C also makes more sense than a FF 35mm, or vice versa.