Re:
I think both SR(Royal) and Sugino(Mighty) did a copy of the Campag. 1044 two bolt post, but that might be too 'old school' for you- late '70s rather than 70s-80s. The Suntour post that preceded the one in your OP pic. was I think a rebranded Sugino.
Any alloy post, preferably one without flutes, can presumably be lathed down to 25mm by an engineer. You could pick up a badly scarred 27.2mm (or whatever) cheap, and get it machined down as good as new possibly for less outlay than forking out for a pristine post in a rare/unobtainable size.