Had the same problem when I bought my Bigfoot (2500/10.4), ended up buying a 2006 F350 DRW, even then you have to be careful, not all DRW are created equal, check the GVW on the door frame sticker, I needed one with the 13,000 lb gvw, (the heaviest one available that series I think) took some searching, but eventually found what I needed.
Even with the dually I'm right at the max when fully loaded for long trips. The truck tares at ~8200, with two adults, full fuel, water, food, Honda 2000, and other assorted "stuff" we scale out at 12,900 lbs. a friggin' tank, but I don't have to worry about a trailer.