A Yuba Boda Boda or Kona Minute isn’t that long. The mediumtails that cause me to break out in a bikelust-induced sweat are about the size of a CaBi, or, at the very least, not that much longer.
Looking at the Devinci Bixi bike CaBi uses, you could probably start the cargo deck right at the seatpost collar and stretch it all the way over the wheel, supporting the deck just over the rear fender; I guess that’d be oh, a foot and a half, two feet of cargo capacity—the length of a jumbo slice, at least. You could carry a pie on that, no problem. It’s not going to be a big deck, if they keep roughly the same design and try to fit the bikes into the same spaces they do now, and, just because of how the seat angles work, I doubt you could carry kids on them…but schtuff? Yeah, I could see that. A CaBi would be a great mediumtail if you tweaked it right.
The real question, from my point of view, would be pannier compatibility. What kind, how would they be provided, and might there be pannier sharing schemes? Perhaps public access kitty litter panniers? A bridge to burn when we reach it, I suppose, but one almost worth planning for now.