The 460 is tempting, and I did cut my big bore teeth on a S&W 29.... It is a bit big though, is the 460 as "Usable" as a 454 only revolver?
I have a 460V, and that's the version that comes with a 5 inch barrel. I've put a lot of 460, 454, and 45 Colt through mine.
View media item 50
Mine seems to favor light bullets and shoots them a bit more accurately, but that is based on off hand shooting at like 75 yards or less. So take it with a grain of salt. Maybe the gain twist rifling works better with fast, but lighter/shorter bullets, but without a rest and test range, I couldn't tell you anything definitive.
It shoots the 200 gr 460 Hornady load like a laser, but I'd never choose that to hunt with. In fact for game big enough to warrant that cartridge, I'd only use that weight if shooting a monolithic bullet.
It seems to shoot 240 and 300 gr 454 Casull alright as well, but the 460 rounds definitely seem more accurate.
45 Colt is really not too accurate in mine. I've read many theories but it seems logical that the massive cylinder jump may be an issue. I also wonder if the slow velocity combined with the gain twist rifling causes an issue with "over stabilization". Basically the twist becomes too fast for the velocity and weight of the bullet, and it throws the trajectory off.
What I'd recommend is if you go the X frame route, and you reload, don't even mess with Colt or Casull, and just focus on buying 460 brass (it's expensive) and download it to 454 levels. You avoid the cylinder jump issue, you avoid the crud ring issue, which can get annoying with high pressure rounds like 454 and 460, and you can always ramp them up if desired.
If you are really only interested in 454 velocities, then as MaxP said, get a 454 revolver, maybe a Toklat or longer barrel SRH, and be happy. They are smaller and much more packable than an X frame, even a short 5" barrel version like mine.