The ZX81 Mechanical Keyboard is a customizable mechanical keyboard that works with both the Sinclair ZX81 and the ZX81+38 modern recreation. All design files, including KiCAD schematics and layout, are available in the repository. The gerber files and custom keycaps were ordered from JLCPCB and wasdkeyboards, respectively. The keycaps come in two versions of the SVG files, one with converted text elements and the other without. The ZX81+38 project is also available as a modern take on the ZX81 mainboard.
https://github.com/swetland/zx81-keyboard