Philip,
I'm posting this to the list so you can't say I didn't do my homework.
I tracked down a 4051 that I saw mentioned on the web and asked about it.
Here's their response:
Greetings Joe,
I have had your e-mail on my to do list for
sometime but the alligators have been chasing me on other chores. Any
how The tek 4051 is about 1976 vintage and it is only recently that we
disposed of them to our surplus place. We had 4051, 4052 ,plotter,
joystick and a printer. I still have all the manuals and microfiche for
them I think.
The address for our surplus unit is <sniped>.
I'm already working on trying to get the manuals and to find out about
their surplus disposal.
Joe