It finally got over 32 degrees today and the 5 foot snowbanks are now only 56 inches. But all this business about gas capacity got me wondering what the big deal is, so I dug out my "Rider's Manual (US Model)" just to check. It's the 3rd edition, June 2010, and state's on the back that the tank capacity is 15.5 liters. Useable fuel is 13.5 liters and reserve is 2 liters. It says that's approximately 3.6 gallons useable and 2.1 quarts reserve. I did a conversion on 15.5 liters and that works out to be a total tank capacity that's slightly over 4.09 gallons.
I still don't know what the big deal is. You need to get gas when you hit 150 miles. (I fill my GS at less than 200 miles.) If that's truly a problem for some reason, maybe an adventure model or an 800GS would be a better fit. Or, if you want to turn this into a distance sport tourer, you could hang some bags on it and a rack and throw a 2 gallon can on the back. Stranger things have been done in the name of adventure.
2007 R1200GS; 2006 DL650 V-Strom; 2011 F800R; 2013 CRF250L; 1995 R1100GS (sold); 2006 Ducati Multistrada 620 dark (sold); 2013 F800GS