We're working on a homemade monofin bolted/epoxied onto a regular fin, to see if this will boost finning speed and yet not wear me out during dives. Once this setup works, it will still have to be adjusted depending on the type of disability and requirements of other users.
As if 1-leg powered scuba diving is not enough, I've gotten into competition sailing on Hobie 16s and Access dinghys. Hoping to qualify for the 2012 London Paralympics, too late for Beijing 2008. I'm also designing an outrigger, steering and sail rig system for a kayak, to make it convertible into a sailing trimaran. This will make it a dive boat platform in between cruising about islands and lakes.
Attitude, vision, love for the sea and most of all, having as much fun, is what will keep us "diff-abled" playing in or on the water.