Saw this while browsing craigslist in Phx, he's got a couple ads posted for it. https://phoenix.craigslist.org/nph/rvs/5573226149.html 33' to the first cabinet,lol... Thats a big 5th wheel TH. ...
You could do it with the 08-10 F450's or the newer F350's with the TowBoss package. Of course the newer F450's also.
I guess the new Dodge duallys have a high tow rating, but I'm not as up to speed on the Dodge trucks as I am Ford.
My F350 has a GCWR of 30,000lbs. I am right at 27,000lbs with my current trailer fully loaded. I might be super, super close with this 50', but I would have a F450 if I owned this trailer.