The attach link is a photo of my Silverado 2500 HD, 4-WD with Duramax and Allison 6-Spd auto, 24ft Pace GT Shadow enclose trailer (28" OAL), with my golf cart pit vehicle and trailer (double tow). The gross weight is slightly under 10K and the 2500 HD handles this towing package without any problems. I do use the load-leveler hitch which makes everything extremely stable towing.
http://www.racingjunk.com/gallery/album/4583/738693