IMO there is only one or two revolvers that meets all of your requirements.
What I want would be something as a bear back up
large caliber type cartridge that could also shoot a lower powered cartridge
I'd like to be able to buy snake loads for it
I'd like something smaller and lighter weight as carrying it as a backup would mostly be it's intent.
The Ruger Alaskan in either 454 Casull or 44 Rem mag.
http://ruger.com/Firearms/FAProdResu...&type=Revolver
The S&W 329PD Alaska Back Packer in 44 Rem mag.
http://www.smith-wesson.com/webapp/w...egory_rn=15706
The 500 and 460 are extremely large revolves and are very very heavy so carrying one as a side arm while hunting would be truely cumbersome. For comparison the Ruger Alaskan weights 2.5 - 2.75 pounds with a 2.5" barrel. Certainly not a light weight but not nearly as heavy as the smallest 460 or 500 at 3.5 pounds and 4" barrel.
The S&W Alaskan backpacker weighs in at only 1.85 pounds and would be the easiest to carry but the recoil is going to be considerably stiff with such a light weight revolver.
Either of these two cartridges are sufficient as a back up, or as homers brother puts it...
something to wander off from camp with to take a dump
Which is honestly what it would be used for while hunting because you are going to shoot with the rifle first and the hand gun last 99% of the time.