Our K2500 sub specs...
6.0, 3.73, 4l80E 4 speed,
2351 payload, 7600lb towing.
We can tow any hybrid built, but run into challenges with stick and tin bunkhouse variants. We never run out of payload, but run out of towing capacity. When worrying about tongue weight you need to understand the different types slide outs. Super slides will have the highest tongue weight. look for smaller slide outs and you will find easier to manage weights.
When we look for stick and tin bunk house variants, we try to find floor plans with small slide out models such as Aspen Trail 2760BHS.

Jayco 28bhs

http://www.rvingplanet.com/models/jayco/jay-flight/28bhs/
They are usually 7600lb GVW or less, and have low tongue weight.