Nice project. The stumble block for these kinds of projects is often the keyboard. It seems tricky to get something nice to use without using keyboards from other products - and then being a slave to that mini keyboard's dimensions and availability.
This project made something that seemed like it could be nice (the page was missing a final photo of the project all put together), on a custom PCB with off-the-shelf switches.
The keyboard is working fine and since it's powered by a Teensy 3.2/LC it can be plugged into any USB host, I'm still waiting to get the keys printed in order to put the working build in the case. The CardKB project is also interesting if you want a keyboard with soldered keys, only "downside" is I2C bus.
This project made something that seemed like it could be nice (the page was missing a final photo of the project all put together), on a custom PCB with off-the-shelf switches.