The trailer we are looking at weighs #5595 according to Grand Design, with a hitch weight of #505. We will get a new tow vehicle to handle this weight, I am considering 1500 Eco Diesel, 1500 Hemi ...
I don't know if you're considering new trucks or older, but let me throw something else into the mix. We love our older 1500 5.7 HEMI Mega Cab (even tho it only has the 3.73 gears). It's got the 2500 frame, rated to tow 7,700+ and the longer wheelbase is great. Wheels are 8 lugs. Ride quality? Probably not as smooth as your 1500 though.