Is it possible to assemble a smartphone with your own design?

Question

3D printers

There are already 3D models of the case, they can be printed on a 3D printer with an accuracy of 50 microns. The question is about hardware.
Are there any open platforms now that could be minimally upgraded? (for example, connect additional LEDs and control them through / sys / class / leds / ...)
How realistic is it to use hardware stuffing from any Chinese on Android for this?

Answer 1

It is quite possible to shift the stuffing from one body to another. Why not. But with their LEDs it is already more difficult. Where to solder them to someone else's stuffing?