I did some sluething. It seems there is just a project done by three engineering students as a final projest to develope hand controls for utility vehicles.
They developed the controls to fit the Polaris Ranger 4X4 EFI, the John Deere Gator TX,
the Kawasaki Mule 3010 4X4 Diesel, and the Yamaha Rhino 660 4X4.
Their design criteria had to hit below $400 total cost.
Check out the website for grants or assistance or let us know if you need help getting this.
http://www.agrabilityproject.org/assist ... od/bse509/