Need one of these wheels
 

Desperately seeking one of these wheels. The tire size on it is 12x6.00-6. I need just one wheel, no tire. Must match this one exactly. It is a 1 piece plastic wheel. Thanks.
http://img31.imageshack.us/img31/7904/img3458s.jpg
http://img844.imageshack.us/img844/2305/img3453tl.jpg

This belt drive sprocket/cog is made ti fit inside the wheel
http://img803.imageshack.us/img803/7411/img3455.jpg