Below is a link to a 2WD bike, which looks like it rides better on snow than a normal MTB. A future potential mod for fatbikers who ride a lot on sand and snow?

http://www.gizmag.com/tretta-awd-bicycles/25203/

Nice looking bike, could do with a chain guard though.

A solution looking, hard, for a problem. I can't think of any traction issue I've had with my fatbike that this would solve.

In my experience, riding two different 2WD systems on bikes, they never overcome the weight-to-utility equation that can be so effectively influenced by technique.

I've also ridden a 2WD motorcycle, the Trailbreaker, and that one definitely works as intended. The difference between fat-tired bicycles and motorcycles being "the engine"... ho ho