if you love the .25-06, then i'd say have someone rebarrel it with an identical barrel, chambered in .25-06 ackley improved 40*, and get a little bit extra out of the case.
Or, if you want a larger diameter bullet, the .280 ackley improved is a phenomenal cartridge, that also uses the .470 bolt face. The ballistics can fall around 100 fps shy of a 7mm remmag. Which is outstanding. Alot of people overlook the .280 ai for a big magnum caliber, but i can assure you, it is an outstanding round. I've been researching the caliber for many many years, and my next build will most definitely be a .280 ai.
If you go .280 ai, i would still stick with a sendero contour barrel. My preference is a 5r rifled barrel, like a bartlein. If you're going .280 ai, i would go 1:9 twist so you're covered from 120's all the way up to 180's.