Forgive me for not having an exact reference. There was a thread on these cameras sometime ago, here or the LF Forum. Some one said that in Chicago there was a company that specialized in Banquet photography. They had a camera for each major ball room, pre-focused for a spot in that ballroom and stored on a shelf with several other banquet cameras, pre-focused for other ball rooms.
Chicago in the early 1950s was home to many conventions, because of its central location, many national headquarters and related entertainment facilities. Only a few business men flew and all trains passed through Chicago, going east or west. This was also home to Deardorff who were happy to make up a very heavy 12x20 for your shelf.
I have only seen one Deardorff 12x20 at an Art Sinsabaugh exhibit. One of these on tripod would melt the 100 pound shocks on my 7x17’s baby jogger. There are pictures of him with the camera on tripod on his shoulder as he walked around. Of course Art had three heart attacks and had died by 53. Then there is Kenro Izu and his custom made 14x20 Deardorff hiking around in the Himalayas. I can only assume there were sherpas.