One of the tutors at the welding class looked at my mock up photo from more of an engineers viewpoint than I had been and pointed out a few things (shock still going to rip itself apart under braking, braking would stop the fork compressing, travel path less than ideal) and suggested a few others like flipping the swingarm around and running the shock under the downtube but I think to make it work I'd have to increase the a2c such that it wouldn't fit the frame and it wouldn't be as attractive.