I know what you mean about the No.1 in .375H&H.
Haven't shot mine for, oh... about twenty years...
Believe me, I am in no way attempting to talk you out of a 470 or 500! In fact, I have a 450 3-1/4 and a 500NE in the works... and they are both single shots!! And I am eyeballing a 475 No.2 (if I can talk the missus out of wanting a new house...). None of which I need or am too likely to use against dangerous game. Just want them for much the same reason as you do.
So, carry on... but please let us all know what you end up going for and how everything works out.

As an aside, there are some very decent and knowledgeable gents here on NE. None of which (in my own experience) would mind one bit giving you some help with deciding what may be just the right gun for you and then working up a proper load for whatever rifle you do end up getting.
You never know, now that you have your feelers out, something just right may just fall into your lap.