OK, so I'm finally able to do one. Found two trashed NEXT bikes, one with rear suspension. Both aluminum 24" frames and front fork shocks, though. Planning to put the rear brace tube up to the seatpost rather than down to the pedalcrank area. Hoping to make racks from conduit and PVC pipe which is very easy to shape, rather than having to buy racks. Really not interested in investing alot of cash in a first build concept.
I'll try it first with the suspension active, retaining option to make it rigid because the springs are probably too weak.
Pictures soon, as I'm still assembling. Same as others I like the concept enough to build one, even though I don't live in a bike friendly area.