Forced back to the drawing board!

My efforts to solve the bottom  bracket ht. issue by adding the section of frame from the Mixte frame were a failure. The change introduced way to much flex in the frame and I can't figure a way to fix it.  I'm probably going to find a larger rear suspension frame and use that instead of two frame sections bolted together.  I haven't been able to find a cheap frame of the type that matches the setup from the pivot point and has the bottm bracket in the right place.