I know we discussed Tutmarc back in the Pit days, and we've discussed the Gibson uprights here.
Bud Tutmarc (who passed away about 3 years ago) tells an interesting story about the origin of the pickup, but there were a number of people working on the idea independently in those years. And Barth and Beauchamp got theirs out first. It's possible that Paul Tutmarc actually made a working pickup first, but there's no proof.
I was recently watching an original Tutmarc
Audiovox lap steel on eBay. I thought for sure it would sell since the opening bid was $999. This is a historical piece. Yet no one bid.
One item not mentioned in these articles is the "App Guitar" built by O. W. Appleton, who IIRC was a music salesman from Iowa. It was a one-off solidbody built in the early 1940s. He built the body and used a neck from a Gibson archtop. He presented it to Gibson with the thought of selling the idea to them. They turned him down. But what's interesting is that the guitar looked amazingly like the Les Paul they came out with about 10 years later. Not much about him online, I read this in a print article in the 90s.