Thanks to the generosity of @oshpark, the PCBs for version 10.2 arrived today. I spent the evening assembling it and updating the code to handle the new button arrangement. Here it is, with the working scrolling text in all its glory:

Please excuse the potato-cam that can't really catch the colors properly, and the dark photo — it's night in here already.

For debugging, I'm using the optional voltage regulator to power it from USB. I'm still waiting for the battery holders for 2×AAA batteries. Once they arrive, I can also try experimenting with a laser-cut piece that will go on the back around the battery holder, to make the whole thing more comfortable to hold.

I also need to prepare all the materials and start asking fabs for quotes — this will be the final result of all this work for making it cheaper.