I would be interested in seeing the design if it is not a lot of trouble. The diameter of the smaller wheels I see on your web site is an issue for my application, so I won't be trying to actually make them the same as you. Mostly I am interested in the general concept of how they were put together. Some images might do the job as well as the cad files, if they are not easily accessable.
Have you looked into reducing the number of the smaller wheels, but increasing the diameter of the smaller wheels? Do you see any barriers to doing that?
You can E-mail the design to the following munged address; joed AT sight-sound DOT com I have access to AutoCAD, Solidworks, and can import several formats as well.
Joe Dunfee