Dave,

I built one on Proto-Board my first try. It was tedious, but worked well. You can build on a breadboard, perf-board or etch your own. Mr. Carlson does not usually do commercially produced boards and the practice is discouraged on Patreon, for obvious reasons. I would not doubt that someone has produced some of these boards, but I do not know of a source myself.

--
Michael Lynch
Dardanelle, AR