Speaking of emulating RL0{1,2} drives, if I wanted to
attach some sort
 of drive emulator to the big fat cable attached to the RL01 drive,
 where would I get specifications on the signals in the cable? 
Chapter 3 of
http://www.bitsavers.org/pdf/dec/disc/rl01_rl02/RL02techDescr.pdf
seems to have some of this.
  (Yes, I'm still thinking of how to emulate
expensive things that may
 die so I don't have to kill them by operating them :-). 
I think it's an interesting project :-).
    Vince