Checkout this extra fin by Kelly Slater to give more drive to quad boards and to take the squirrel effect away from quads.
I know that it is not new as it is already being used on wakeboards etc
Might be what the quad riders have been looking for.
i71.photobucket.com/albums/i123/doc808/
http://www.mdsurfstore.com/product/von-sol-the-nubster-fin-mini-stabilizer-fin
