If you are looking for a trailer hitch to mount on your RV then the highest rated capacity is the Curt Trailer Hitches parts # C13702 and # C13701 which are both rated for a max of 6,000 lbs towing when a weight distribution (WD) system is used. These are the same hitch with the only difference being the 13701 has a 2" drop for the receiver.
We do have the Ultra Frame Service Body Trailer Hitch Cross Tube # 41991 which has a 16,000 lb towing rating but I'm not sure if it would fit your... view full answer...