1) At first I thought jock itch was the Mamiya equivalent of Schneideritis, but I got it - fun-fun-fungus.
2) Perhaps PM would be best way to discuss your price - I do tend to like doing things the hard way, but a lens with shutter that works decently would make the project more usable. The hacking part is half the fun.
3) I have a PM offer of parts from a totally frozen one, so that might solve the hack needs, and yours may solve the functionality part.
I haven't shopped much yet but what you want is probably the reality check...doesn' tmuch matter what other people want for theirs!
Thank you
Murray