I just got word from Me Solving Timespy that there isn't really any solutions shorter than the TFT one I've got now, and so it looks like Tetrinsic 2.0 with TFT will be the only version worth persuing if Timespy doesn't cause this solution to fail, meaning that I'd have to go back to my Tetrinsic 1st Generation days.

I'm also thinking of Tetent, and how I'd connect the two halves. Perhaps it might make sense to have a USB host controller on the PCB so that, ideally, a master Tetrinsic on one side can connect to the other side.

Me2: Why do you need USB to connect the two again?

Me1: Wasn't it for a wired Tetent connection and for audio?

Me2: With #T^2 TyMist [gd0138], I no longer need audio in Tetent.

Me1: Oh yeah. That's right. 

It might still be useful to quickly transfer over LCD gifs/videos between all the Tetrinsics. With up to 16MB of flash, it might take a while for all Tetrinsics to update through I2C. I probably should try it first and compute a solution if it actually becomes an issue.