Down here, in the Antipodes, I haven't really noticed any that I could describe as "... just a neck on a stand ...", but I've seen several instruments that have a full bass fingerboard and a rather diminished scroll and a body that is about the size of a cello on a 'weightwatchers' program.
I guess that means that the instrument has enough acoustic output to hear in practices, or even hold its own in a quiet session, but the spike that raises it to normal bass position can be slid back inside the body and it can be carried in a gig bag that's little bigger than a jumbo guitar's.
One of these, now played by the lovely Liz Frencham, of Jigzag, has been enough to stop me suggesting that the petite and vivacious Liz should take up mouthorgan! ... and it sounds just great!