Shortest possible I'm guessing would be to make a new stinger that had a 1/2" hole cross drilled then thread the hole so a 1"x5/8 bolt could be screwed in to each side instead of a pin. You'd need only 1 1/2" max on each side and it would never rattle.

Reading back I guess this is kinda what EDL suggested.

What if you get a wild hair and buy a Jetski? Wahoooo..