Personally I wouldn't want to commute or tour on a bike with big, heavy, fat knobby tires -- but your needs could be very different than mine. The roads are good where I live, and I rarely if ever have the need to venture onto dirt roads, trails or so-called fire roads. Actually, I wouldn't know a fire road if I saw one.

Have you looked at the Salsa La Cruz? It seems to have the same features you like in the Fargo, yet it uses 700c tires (and can fit some pretty big ones). It also has disc brakes. Yet you could put regular road tires on it and ride fast if you choose.