I'm loving this thread and all the threads on utility bikes.
So far I have collected an unknown 26" girls mountain bike in purple and black on trash night a couple of weeks ago. Marked "Pro Class Outrider". I was going to black over most lettering to theft-proof it and make it read "ass rider", but that doesn't fit me and I don't need to explain that to the neighbors...
I stripped that bike to it's frame last night. I kind of felt bad because was working pretty well.

It needs internal cables for the shifters and pedals. And a degreasing.
I also picked up an old, rusty, Murray bmx bike tonight. Gray with peeling camo stickers and flourescentorange/pink trim. It's handlebars froze stuck 45-degree to the right. Used PB Blaster, 80-90w gear oil, and cable/chain wax to free it all up. Front tire is flat and the chain is 'lumpy'. It has cool orange/pink apehangers though.
Please post photos of the back end of your (non-welded) longtail homebuilts so I can learn how you all fastened/connected everything since I don't have access to a welder. If I can get everything bolted together right the first time,

then I'll just have some welder melt everything together properly. That way I won't have to pay them to BUILD & weld the beast.
I can't wait to get a cargo bike on the road. I hate driving one mile in the Element to Lowes to pick up 2 x 40lbs bags of water softener salt every two weeks. And I'll use it a LOT more than that.