The swashbuckling adventure of Captain Blood, written by Rafael Sabatini takes place in the town of Taunton. It was made into a film in 1935, starring Errol Flynn. Given Lucas's viewing habits, it's plausible he saw it and picked up the name of the rebellion's snow mounts from it.
Given the lack of an ocean around the above Taunton, it's probably not that Taunton in question; nevertheless that also exists. Who knows if it played some distant role?