I believe that WV gunwriter Richard Mann created a 25 (257) Creedmoor that he calls the 2-Fity Hillbilly over 3 years ago.

If I get the itch to shoot a .257" bore rifle any time soon, I'm probably going to shoot a 25 WSSM before heading down a new path.

I've got 6MM and 6.5MM Creedmoors, so a 25(257) would serve what purpose other than to attempt to satisfy my curiosity?