Not sure about consumer vehicles that come with the standard pickup bed, but on the commercial/chassis-cab vehicles Ram advertises such on their website. It's actually interesting to see the differences in advertised (and probably placarded) capability between the consumer and the commercial/chassis cab version of the same model of truck.
I suspect the commercial/chassis cab truck weight ratings are intentionally being de-rated for life expectancy of fleet usage at (or near) max weight capacity for the vehicle's life. Granted I could be wrong and there's something about a standard pickup bed that makes a truck super powerful ...but I doubt it.
Either way I'm inclined to go with a flat/stake bed configuration with under-bed gooseneck hitch....at which point I can buy whatever type of trailer needed is to hauling whatever I need while also retaining use of a flatbed for loading stuff by the pallet load (which I can then unload with my tractor). Just seems like the most flexible option to me even though it means more tires to maintain (when compared to the larger hooklift truck route).