Just for the record there is a couple of Yahoo groups that discuss constructing these kites and a free program you can download for designing your own kite. (
www.foilmaker.co.uk)
I am thinking about making one at some point.
The kites used on water for the guys with the surfboard, wakeboards etc., generally have a leading edge spar which is pumped up like a bicycle tube. This is so they stay afloat if they touch down. Normally they use a kite which is proportionately too large so they are a bit overpowered. A friend has one and he tells me that after a session of kiteboarding your Abs are pretty exhausted.
There are lots of kite makers out there. Ozone I hear is one of the better and Naish (Robby Naish of windsurfing fame) makes them. (his company) His dad was pretty heavily into Hobie Cats in his younger days.
Anyways the web is full of info on them.
I am buying a cat or I would be buying a kite for kitesking and or boarding. Can't have everything! Am buying some new living room furniture. Gotta be fair!