I am casually truck shopping (waiting for 2014 models) and trying to fit a tow vehicle to a future 5th wheel. Most of the 5er models we like are in the 9000lb-11000lb dry weight and 12000lb-14000lb G...
My SRW '09 F350 pulled our 18,000 lb. Cyclone very, very well. But we were about 1000 lbs. overweight on the rear axle. That necessitated a dually for that reason alone.
I still wish I had an SRW instead of my dually. Just easier to drive around town, etc. Plus, stability was NEVER a problem pulling the Cyclone on the interstates. The 370C we have is almost 45' long.
Here she was the day we brought the Cyclone home. I still miss her. :(