Combine this Bottom Bracket Cartridge 206mm
with this http://www.sickbikeparts.com/catalog...B-Conv-Kit.jpg
All on the smaller type three piece bike shell. To get a J shaft and a pivot point all in one shot..
The best Idea I have come up with yet. Cut the extra large bottom bracket to size. Take it to a drill press drill the end holes deeper re-thread to original thread [note to self prolly gonna destroy a tape mebbe not]. Invert the two adapter pieces [races] grind down to clear the threaded ends to the bottom bracket. Use washers as well.
Find two races weld them to my rear trailing arms to match the adapter pieces they could move independently on the same shaft. Sounded good for a moment still thinking it through.