http://www.naodesign.net/donk-pro.htm
in the 4th picture, you can see the relative size.
I have a feeling it is a smaller wheelbase than the outside, with the edge lifted slightly to provide some ground clearance. The further the wheels from the outside, the more protected they are, and the less ground clearance you have. I get the feeling that if you're not on a rolling hill, you could high-side this thing very easily.