Hi there, BBall. I totally go with the concept of a .44 Magnum revolver to defend against things with teeth that don't like my aftershave... my own carry piece is a Ruger Redhawk with the 5½-inch barrel, full loaded with Garrett Hammerhead rounds. These have knocked over a charging grizzly - a superb performance from even a rifle round, never mind a handgun! When not backing up against such things, it's a fine hunting and plinking revolver (with milder rounds, mark you...).
I agree that a shorter barrel (i.e. 4") is just about as good as a 6" ballistically - with the 2", you lose too much velocity, and the muzzle blast is fearsome! However, there is a very important point to consider here. Do you plan to use the weapon for hiking and/or hunting in Canada at any time? If so, be aware that you can't import any handgun into Canada with a barrel less than approximately 5" in length. This would prevent you taking the shorter-barrelled Mountain Gun with you.
Finally, a word on "toughness". I've seen several S&W Model 29's and Model 629's blasted into reverse rotation of the cylinder after about 80-100 rounds of heavy loads such as the Hammerhead. This is NOT GOOD! IMHO, the Ruger Redhawk is the strongest "standard-configuration" revolver on the market, and is specifically listed by Garrett Cartridges - with its sibling, the Super Redhawk - as the only one able to use their heaviest loads. I traded in my old Model 29-2 on a Redhawk, for strength and for Canadian considerations, and have not been disappointed. Yes, it's a bit bigger and bulkier, but when the proverbial brown substance hits the rotating air mover, I want all the strength and power I can get!
Good luck in your search, and enjoy whatever you eventually buy.