Neat concept. It’d be interesting to do a spin on it that expands it to a 12”/13” footprint, allowing it to have a full keyboard, making it thinner (since components can be spread out), and making it more practical for tasks like writing. Think something like the defunct 12” MacBook, but with a minimal UI reminiscent of an 80s Mac on a grayscale display.
There are e-ink tablets that can have a keyboard attached to them that kinda approximate that, but I’ve always found the KB-tablet-stand form factor clunky at best, and they tend to run some Android derivative which is going to feel slow compared to “bare metal” software running on an SBC.
I remember seeing flexibl eink displays maybe 15 years ago. iirc it rolled up into a toothpaste sized tube. That would be super cool.
The larger alternative that comes to mind is the ClockworkPI [0] uConsole and DevTerm devices, although they seem to have poor availability or long and variable lead times. Beyond that you're into touching distance of x86 laptops with the GPD Win type micro PCs.
[0] https://www.clockworkpi.com/