I have a 12" for a encore, using 250 grain xtps it has put down three deer on first shots each time though the lungs. Never going more than 10 yards from point of impact.
If I were to cut a barrel down I would look at 10" real seriously, I recently bought a 10" 44 mag for a contender and I feel that is the best balancing hunting handgun I have.
Got any friends with shorter barrels your could try out?
If your looking for the magic length for the best ballistics, this will change from powder to powder.