Now with all models above the 2100 using the E450 chassis, PC could build a large capacity model. Larger holding tanks, water tank and LP tank. Build it so the tank capacities are accurate. My fresh water tank is rated at 31 gal., it holds only 17, 46% less than stated. My black tank only holds 17 gal., 26% less than stated. These capacities are no larger than some of the class B's out there. How about 35 gal fresh water, 35 gal black and gray, and don't use the outside tank measurements to calculate the volume, go by what the tanks actually hold. 18 gal. LP tank. Anyone interested?