I used an older NEXT suspension rear end for my first longtail because I had these two trashed bikes. Looking at newer NEXT suspension bikes, I've noticed that the construction has gotten way flimsier.
So I'll be re-reading the 'sticky' again, but the thread talks and pictures mostly about the front frame, not the rear.
I'm wondering about: if one [my neighbor/friend] was planning to do another or a first one. What's brand/model/type of old suspension bike should one be trying to 'find' to salvage for the REAR add-on extension? Best construction, configuration, features?