So I've spent the past 6.5 hours working though Fusion 360 crashes to bring Tetrinsic v361 into existence. I've replaced the old 1.47" pad with a new custom pad for a PCB that connects the two screens, converted the FPC of the displays into sheet-metal components (so that I can adjust the bend radii and position) and adjusted the pressure plate, as seen below.

The routing of the PCB was a bit of a rushed job, but I think it still turned out elegantly. I havent' really done all that much in terms of silkscreen though.

The pinout of the connector is shown here:

The pins were chosen such that it was possible to route the traces on the Tetrinsic PCB. Sadly, I had like 3 crashes just doing the last trace. This reminds me of what Fusion 360 3D design used to be like. It seems I'm only getting crashes when routing a trace.

I'm also thinking about using 4mm alignment pins for the BLDC too, to reduce the amount of unique components. I was planning to use that extra space on the sprocket for a grub screw, but I don't think I'd be able to fit it in anyway and a friction / glue attachment should suffice instead.

Now that I'm writing this log, I'm looking at the cutout for the 1.14" screens and it seemed like I should reduce the width to increase the strength of the pressure plate due to more material available on the sides:

[Spoken like an Apple executive who's summarising a new product as the summary slide animates in]: So there you have it. After 361 saves, this project concept has grown both in size and featureset and is now electrically and mechanically complete (unless I'm forgetting something). I won't know if it's manufacturable until I try, though. 

Oh wait, there's something not quite right about the pressure plate fillet screensnip above...

Ah. Fixed. Ok, 362 saves.