This is a cool idea
Thanks!
As far as inspiration goes, I'm not 100% sure where the idea came from.
The majority of it came from the fact that my double rears up front flex waaaaay better than my single Taco rears in back, which is fine for climbing up, but brutal for decending. I started making plans for 3/4 elliptical, thinking that would solve my issues. And it very well may have worked. But it seemed too likely for something to go wrong, and too many loose ends to figure out. Inboarding the springs doesn't solve all my problems, so I'll just inboard everything. 
I've seen lots of guys chop their frame and tube the rear so it's narrow, mostly because it's rusty and they're linking it... But I've never seen anyone else narrow an existing frame. So I thought I'd try it out. Something new, you know? Besides, it gives me the opportunity to reinforce my frame while I'm in there. 
I like the way you think.
