I compared the size of my pinephone with a bluetooth keyboard of mine. I feel comfortable thumb typing on this bluetooth keyboard and there is still some room. I think an optical trackpad and arrow keys can be added to such a keyboard layout, with some adjustments.
![[Image: IMG-20200903-005657-8.jpg]](https://i.ibb.co/FxwQh7W/IMG-20200903-005657-8.jpg)