Well, certainly there have been many fine USA frame builders who preceded Eisentraut, but he was the bridge to the road bike dominated modern era.
Watsyn was really from the old school... 6 day racing, etc. Peter Nye or Jeff Groman, among others, could probably go on for hours on this topic. I really wish Jeff would finish his book or movie or whatever so I can learn more about this age of bikes and their makers. I would like to know more about Pop Brennan and I have heard bits about a Canadian builder, "Doc"___?, who was famous for his refined and artistic lugwork and still was a high demand 6 day bike maker....
I want to add to what has been said about Uncle Albert is that extreme eccentricity is a thread that runs through many top artists/craftsmen. In my earlier life as a painter, I got to meet a number of really brilliant artists, and studied those from earlier times, and I would say that there is a very consistent tendency towards irritability, egocentrism, and moments of depression followed by elation. This seems to be the magic mixture of creativity!
I have one of those seminal Eisentraut 'A' frames (that Brian Baylis refinished very accurately) and I feel this piece of metal work transcends its "tool" function and becomes sculpture, yes, "art!" I think what is so interesting with Eisentraut is that, like other art, he observed and adapted the forms that preceded him and then moved onto new variations that no one had done before him. Really that is the essence of the Avant Garde approach that we have come to worship in the 20th Century.
My 2 scents (!) Dale