Sinclair's ZX81 was about the first inexpensive home computer, and its bill of parts was reflected most infamously in a decidedly unpleasant rubber membrane keyboard. Now, more than forty years on, is a ZX81 mechanical keyboard designed to execute all that machine's clever features–with keyswitches that finally make them a pleasure to play with. Creator Brian Swetland provides schematics and files at Github: see more on his Mastodon feed.
The custom keycaps were ordered via wasdkeyboards: https://www.wasdkeyboards.com/61-key-custom-cherry-mx-keycap-set.html
In the keycaps directory there are two versions of the SVG files, based on the template provided by wasd. The "paths" version has been converted to paths and is suitable for submitting for an order. The other version keeps the text elements as text for easier editing, but must be converted to paths before using for ordering.
Spotted via Hacker News, where this effort from the early 1980s is the top comment: