xD My idea is actually sort of similar to LadyDeath's. But mine would be a single player only mod and be used mostly for making epic replays and practice.
What it would be would be that you have tori standing in the center of a group of poles (think a circle for now, but you could get creative with arranging them.) The poles would be all different heights, and each one would have something extending from it that would hold a joint.
Here is a really crude drawing I made in MSpaint. The green lines would be the poles, the black would be limbs, and the red is the joint.
Hopefully the end result would be a cool little training thing, like when they hold up multiple boards in martial arts and someone breaks them all in one jump.
This is all based on my idea that joints can be used like this...if they cant than I guess its boned...but how about it?
Why not just use Uke as a target (his neck).. or make Uke into a target because then you'll score points instead of having points done to you for hitting an environment object..