custom circuit board or can an existing one be adapted?

[Legolessed]

Im starting to plan out a custom phone mod to add a slide out keyboard to either a hisense a7cc or a hisense a5 pro cc. I have lots of experience soldering and working with electronics and am trying to make a plan for this build.

 

My initial plan was to try to adapt the slide out keyboard from another phone into this phone, originally using the unihertz titan keyboard, but I started to look more towards landscape slidephones and thought maybe trying to design a custom circuit board might be a better alternative. Im willing to spend a lot of time learning how to do that but I wanted to know if thats even feasible or if something like a custom keyboard pcb, finding switches for that board and everything related to that would be prohibitively expensive or impossible to access.

 

Another idea I had was swapping screens with another design such as the cosmo communicator or unihertz titan, but finding e-ink panels by themselves is also difficult

 

I know this build isn't cheap or practical, but I love color e-ink displays and physical keyboards, and have a 3d printer and cad software and wanted to give it a go!