I remember Wright commenting in "Voyages Of Imagination" that the Zimmerman name was in early scripts that she was given for reference, and apparently there were plans for the Doctor to take the name of his "creator", but it was ultimately dropped.
I had a magazine article calling him Doc Zimmerman from just before the premiere. He was supposed to be a holographic impression left by the original Zimmerman (Voyager's assigned CMO) before his death.
How often have you heard some bugger say "Turn it up to 11" this month?
A friend said it two days ago.