It could be a fun, quick run because you can cause a ring out in less than 1,5 seconds. However, manipulating enemies to stand still for 1,5 seconds seems to be impossible, and I have no full grasp yet what are the second best outcomes.
Basically, you can do cancelled forward stepping with Kage to achieve an extreme speed forward with which to push enemies over the edge. Kage also has a good attack f+B that pushes enemies forward a bit and can speed up the end of a fight. Second fastest character is Akira with his forward turbo A movement, which can be equally fast than Kage's fastest movement. Kage is a tad slower with turbo A than Akira, but switching to it from forward step cancelling can in fact manipulate the enemy behaviour.
Speaking of which, manipulating enemies is somewhat hard. Apparently input before a battle begins doesn't effect anything, so you're pretty much forced to do the manipulating during the round, which of course wastes time. Stopping for a moment can change and delay the next attack for example.
A test run of the first two fights:
http://www.youtube.com/watch?v=nyDaKI9AB14
It uses the default settings, except for difficulty, which is set to hard. For pure speed I'd be tempted to set the options to the cheapest possible (1 round to win, 10 seconds round time), but that might be a bit
too cheap.
EDIT: for those curious, here's the
.gmv file.