i wish you a happy new year! Time flies, I got all your Emails but replied only to a fraction. I became a father and studied industrial design in the meantime.
The project is still semi-alive. I have put together the production files (dxf, tell me If you need another format) for the Archivar as well as some hints on the hardware we use. It's just raw files, not a comprehensive manual but together with Daniels instructions https://diybookscanner.org/archivist/
one should be able to build this.
It includes 2 versions of the base, one to be cut from 18mm plywood, and one to be cut from 8 and 10mm plywood that's than sandwiched together. (Useful when eg. your laser cutter can't handle 18mm plywood.)
Everything is in mm/metric!
You'll find that archivar.net is no longer parked but now forwards to www.davidsmutny.com
where you'll find the files.
I hope that still someone finds this helpful in their quest of building a scanner.