Roll back carriers utilize a long stroke horizontal cylinder between the longsills that allow the body to push/pull from the truck. They also use a very long body length for the CA of the chassis. For example a 120" CA would normally have a 16' platform or van body but as carrier the body length is approx. 19-20' in length. This allows for short piston type lift cylinders to raise the body and keep the approach angle low. Winches are generally drum type and attach to the front of the body. So if your thinking of adapting your dump hoist to this you can forget it. Whole different animal with completely different characteristics, heigths, torque, etc.
I'm not going to say you can't build one because I know I can but I've been in the business for 40 years which is about twice as long as I see you've been around. All that means is I'm a really old fart without your energy or enthusiasm for these things. But at least I can still answer some questions.
