Get the 460 S&W. Personally I would not shell out the extra clams for the Performance Center version but if you are really nuts about that version, why not? The 460 will fire .45 Colt with relatively low recoil and if you reload cast it will be on the cheap.
As much as I'd love to have a S&W 500 'just because', the 460 is WAY more versatile and due to the higher velocities the energy can be pretty close to the 500.
The ability to shoot .45 LC, .454, .45 Schofield, .460 S&W, and (with a milled cylinder) .45 ACP and .460 Rowland is pretty cool.
That was my first choice anyway.
First order of business- Finish ream the cylinder throats