I know that steviodosound is gonna love this link!
These are some tape recorder directories from 1955-61 (there are 4).
They were generously uploaded by Tom Fine and he posted the links on the Ampex List.
Some very cool stuff especially if you enjoy looking at old ads like I do.
http://www.archive.org/details/AudioDevices-TapeRecorderDirectory1960-1961
You are right !
I don't personally have any of these but a friend of mine has a few in his literature collection. I also remember pouring through the Stereo Review annual Tape Recorder Guides in the mid-late 60s era looking at features and comparing specs. on machines I would never be able to afford. I do have a couple of Allied and Lafayette catalogs from that era to look at machines that I still no longer can have. But I do have plenty!