Been staying at a nice RV park and watching rigs come and go everyday. The amount of 3/4 rigs pulling 36+ Fivers is about 90% compared to a Dually. You have three choices buy a smaller Fifth Wheel, Buy a Dually Truck or buy the rig you are looking at and keep your truck.. I don't think you would have any problem. A guy came in the other day with a 40+ foot Cyclone triple axle towing with a 2500 short bed Dodge (that did cause my head to do a 360)
Half the people on this forum are probably towing righ at or out of spec.