I think what would get people interested would be pre-made parts kits with the electronics, and other non-printable stuff ready, so that all they have to wait on is the printable stuff. At least that's what I want. I don't mind doing projects like this, and don't mind assembling, but the thing that stops my projects dead in the tracks is stuff like electronics that don't work (like maybe I soldered something wrong). If I had "plug-n-play" electronics kits, and the other hardware, and all I had to do was get someone to print the other stuff, and then assemble, that would rock.
Heathkit for n00bs, basically.
btw, for you youngins who didn't grow up in the 80s, you missed some *awesome* project by the Heathkit company. Radios, robots, computers, all shipped to you in kit form, and you soldered and assembled.
Except I don't want to solder anymore - many a night was spent cussing because I had a short somewhere in my circuits.