Agree, mate. Te classic look of the No 1 cries out for unusual calibers, an that's part of my sinful behavior.
I buy one now and then, and have it rebarrelled, but not always in the N E cartridges.
I look through books and start wondering: what next? So far they've been modern ones, the last one, just finished,
is in 9.3X64 Brenneke. I know of builds in 470 and 500 NE, and wildcats of all variations.
Anything over 500 NE means too much material has to be taken out of the block and action to stay safe.
I'd like to go with either the rimmed or rimless 7X64, but brass is near non-existent for the rimmed version,
and the 280 Rem is a virtual copy of the 7X64.
Ahhh, well, I'll keep thinkin' despite the headaches it gives me...
Cheers, mate