Not only was it used in production, from the first-hand anecdotal accounts I've heard, the VAX/VMSclusters were near-z/OS level of reliability. For a brief time, it was used both in mission-critical environments as well as in academic institutions (basically two of the three large markets that existed during that era).

Every 10 years, the same thing gets re-invented. Take network block devices/clustered sharing. VMS had high-availability and each node you joined could use it's local disk as an aggregate resource. In the 90s you had AndrewFS and CODA (CMU's golden age IMO). Then Linux had the whole DRDB era which gained traction about 10 years ago right around the time Hadoop was gaining traction. OpenStack has Cinder. 10 years from now we'll have something else.

Anyways, great points and good post. VAXstations are available on ebay for pretty cheap, but I'd personally go with a hobbyist OpenVMS Alpha license running on ES40. I threw a setup together a few years back and it was neat. Thanks for the data-sheet, my father will get a huge kick out of it.