Is there any way of getting psql to display the name of the currently-connected server in its prompt, and perhaps a custom string identifying e.g. a disc set, without having to create a psqlrc file on every client system that's got a precompiled psql installed?
No.
I've just come close to dropping a table that would have been embarrassing because I couldn't see which server an instance of psql was talking to. Now obviously that's due to lackwittedness on my part and it could be cured by installing psqlrc files- but this might not be a viable option since it means chasing down every psql binary that's been installed on the LAN in an attempt to protect users from self-harm: far nicer if the default psql prompt could be loaded from the server.
Not every binary; every user profile.
If you need it, maybe employ some company-wide user profile scripts.
That's not so hard if you use Linux/Unix environment; just use /etc/rpofile to enforce a common policy.
-- Mark Morgan Lloyd markMLl .AT. telemetry.co .DOT. uk
[Opinions above are the author's, not those of his employers or colleagues]