Yes, the .250/3000, etc.

And now the .260 Rem; why a 1/10 I have no idea when 1/8 was the standard 6.5x55 twist.

A 1/8 twist .243 or 6mm Rem shooting 135 grain bullets would actually inspire me to try that cartridge, and a 1/8 twist .257 Roberts shooting 140's would be a peach for my purposes!

All those are excellent rounds as-is, but a quicker twist would IMO make them even better, and in most cases wouldn't hurt much if at all in accuracy with the lighter shorter bullets.