I just installed a rear mounted winch on my 500 Scrambler. Most of the Scambler winches I have seen were the front mount to the bumper, but Warn makes one that mounts just under the tail light to the back frame. I have a rear rack on this Scrammy, so I had to drill through one side of the rack mounting bracket. I haven't ridden it yet, be we are headed out for a week of riding the Ouachita and Boston Mountains of Arkansas.
Check out the pics:
Scrambler Winch