Given the PiZero has the power and USB connectors on the same side, and also that it doesn’t have an ethernet connector I had an idea for you…
I was thinking of something along the same lines but without the stacking and cases. Just a board that is the same size as the Zero but adds the B+ usb hub chip. So adds on the opposite edge four usb and Ethernet. The power and HDMI is passed throw with the hdmi gowning to full side. Be a nice little ‘PirateDoc’ for setting up a board before it sets sail into it’s project…
(see what I did there) ;)
My thought about stacking was that with ethernet connections and with such a cheap computer, you could create communicating extremely parallel systems. And in a neat single, expandable package without all the extra wires that similar arrangements have needed in the past.
I think this is the kind of chip the active inner parts of the sandwich would need:
and their demo board for this
is pretty much what it would need to contain, but with a different arrangement of connectors. This chip has a USB hub as well as the USB to ethernet converter and the Ethernet hub, all in one component, so the single PiZero USB could fan out into say two USBs exposed on each layer and the ethernet. Only connectors are needed in the bottom layer, and the top layer is just a plastic slab.
Someone already did it!.. Might you sell it Pimoroni?