bump bc I have something to contribute to this.
I made some bumper boat graphics for UN that were never used. The idea was to make a water sumo/fallout/KOTR event, where instead of slashing about, you use the boats to push each other out of the arena. The boats have momentum that affects the force of the bump, and when you bump someone, you would go back a bit too. I'd be willing to send those sprites this way, even.