My full time job is pcb design work and as a hobby I enjoy experimenting with new design ideas. This was one of the more challenging designs I've worked on in a while. A few times I'd given up on routing it. Evan using four routing layers I found it tough. The idea was to hide the bezel of the display behind the board but have sensor components on that same board. It would look something like a little tiny television. This first revision has issues but the design so far can possibly help others in some way. Full credit goes to Adafruit for publishing the Feather M0 design files along with the bootloader. I used the Feather design to create the schematic for my board. Credit also goes to Microwavemont on Tindie and the SSD1331 library that he has on his site compiles error free using the Arduino IDE.
I like the back-mounted display! I'm sure cutting out the most valuable chunk of PCB routing space didn't make your job easier...