ok I spent the last hour going through all 29 pages of posts you made. I remember you describing using a electric chair like a Hoveround or whatever for parts. Talking about using the joystick for the forward and backward movement. I couldn't find the post. Maybe it was in a PM.
Don't know, but here is some links to articles on it.
http://www.homesteadingtoday.com/specialty-forums/survival-emergency-preparedness/vault/466526-garden-helper-machine.html
http://www.builditsolar.com/Projects/Vehicles/GardenHelper/GardenHelper.htm