I can't imagine what a rifle like that would be good for. Too big and heavy to hunt with, too much recoil for shooting from the bench. Why?
And yes, a new Mark V deluxe in 460 Wby is about $2300.
Also, I know it's been done but the 1"-16TPI threads on a Ruger #1 barrel shank don't leave much meat to support a cartridge that big around running at 60,000 psi.