I'm a contractor and lots of guys I know have those 4-6 ton street dump trailers, some gooseneck, some ball hitch.
I personally just have a tandem axle 16' 7000lb trailer and a 12' single axle 3500lb. I doubt I would ever fool with a dump trailer, I think I would scour around to find one of those isuzu NPR single axle dump trucks used.
I always figured the NPR had the transmission and axle to handle that much weight better than a pickup. Sure wouldn't want to burn a clutch pack out of my transmission knowing I was hauling materials meant for a dump truck.