We've been on a bit of a three-wheeler kick. Maybe it started with the all-new Slingshot's unveiling, or maybe it's the Scott Sociable ex-WWI gun carrier turned weirdo runabout from a short time ago.

While most people picture a four-wheeler when they think of an ATV, the category is far more diverse than quads. Some of the earliest examples in the segment rolled on six wheels; from those initial ...