Thank you for the links. Seems those threads have gone quiet. It might mean that the developers had no plans to offer a commercial outcome, but they supported open sourcing, or demand isn't there.
You're correct in that my concept appears to be a hybrid of the two links. USB powered plus direct cable free installation. Seems Probe Offset voltage adj. is not an in demand feature which answers one of my constraint concerns adequately.
The build in the first link is remarkably close to my physical concept, leveraging the proven laser cut acrylic approach to sandwich the PCB as I did with the SG 504 leveling head since 2016.
Well...it's still a back burner item for now.