One more device I forgot all about:
Akyumen Holofone & Falcon Tablet
https://www.youtube.com/watch?v=D3mGK52INOU

It's a 7 inch phone / phablet thing - that runs full windows 10, has 128GB storage, 4GB ram AND a projector - all packed into that 7inch diagonal thin rectangle.
This would probably be Win 10 only though I am guessing, without much scope for messing about on it & installing other things. Quite expensive I think too

I guess that one is more of a "Look at the kid of thing that COULD be done".
Chuck out the projector, add a sliding keyboard, and the insides of this gizmo seem very impressive. I also came across a thing called the Pico8 on Pocketchip which has a really thin clicky keyboard.

These things are doable- Manufacturers just don't seem to want our money.