hey guys.
I too want to help anyway I can. This is a great project.
I did some searching on the net and found some things/sites that may help;
I saw this;
It was here;
http://www.wheeleez.com/
I thought maybe they would have more info on it, but have not contacted them yet.
Their site has some better prices on wheels and such.
I also found a guy who makes his own wheels for the beach. He setup a How-to of sorts here;
http://www.geocities.com/mec_coleman/tip13.htm
anyway, hope that helps some.