Very cool that you don't let just having one arm limit the things you do too much.
There is a guy who is paralized from the legs down that kitesurfs with flysurfer kites and the help of his friends.
Apart from modified bar setups you should look for a kite with very light bar pressure. I have a Flysurfer Pulse that has very light bar pressure and a lot of depower. I have found it much easier to fly with one hand when rescuing someones board. The bar pressure on the Pulse is also adjustable.
My guess is that it could be made even lighter with a simple modification to the bridle. Another thing that would be to your advantage is when the kite is set to full soft steering it actually turns faster. This is because flysurfer kites are fully brideled.
The Pulse is also disgustingly easy to relaunch which in your case could become a problem with most kites. I have repetedly relaunched the Pulse using just one hand. Other kites relaunch well, but they are more technical to relaunch.
As soon as I have some wind I'll do some "1 handed" experimentation with the kite and let you know.
Also I would recommend riding with a larger board. With a larger board you will need less power to pull you so you will have less bar pressure in general.
Contact Armin at Flysurfer. I'm sure he would go out of his way to help you out. Flysurfer is a German company and there are lots of guys there flying Pulses. You could also ask around on http://www.foilzone.com
Here is a link to a video of the paralized guy and his friends.
http://www.flysurfer.com/Gallery/v/vide ... s.avi.html
Again it's great to see you determination.