There should be more /785s out there than plain /780... IIRC, most /780 were upgraded, as the "old" /780 had some EMC issues in the field? Am I dreaming this up?
The thing that always made me wonder is where are all the 8600's. The 8600 was apparently the best selling large Vax, outselling the 780 and 750, so what happened to all of them? They weren't any bigger than a 780...
C