I use a 2011 GMC Sierra 1500 with the 5.3L and 3.42 gears. I pull a 30 foot R-Vision Trail Cruiser. It has a dry weight of 4370lbs plus gear, propane, battery, A/C, water it weighs in above 5000lbs. The truck does well around town, flat highways, and short hills. I need to slow down to 55mph to pull up any decent grade, otherwise it tows at 65mph without any problems.
I can just tow it with my GMC Acadia if I have to, but not with water or much gear inside... it is a scary ride with the SUV and it is actually within the limits legally for that vehicle. I prefer the longer wheelbase of the Sierra and the added payload and towing capacity make light work of the trailer.