Marcel Erz has reverse engineered the Model I ALPS keyboard PCB. He says
This project is a faithful reimplementation of the ALPS keyboard PCB of the iconic TRS-80 Model 1 computer. My revision, the E1, is designed to replicate the PCB design 1-to-1 of the original down to the traces. The entire project is available under the MIT license.
Visit the GITHub Page for gerber files, Bill of Materials (CSV and PDF formats), layers exported in PDF and SVG formats, and full schematics of the E1 replica which is 1:1 to the original G board.