I agree with the antirollbar analogy - hadn't thought about it but that is about right.
Matt167, can we have a little more info? If it is the fleetline you are doing this on, does it have leaf springs? If so, bad ju-ju there. You will have some serious binding issues as the springs want to go straight up and down while the ladder bar travels in an arc. There are ways around this but the project becomes more and more complicated. Many on here can give you good, safe advice - just more info so's we can be confidant when we tell whats best to do.
Those long radius rods you see on the rear of an old hot rod that run up on the outside of the frame rail? Real bad ju-ju there. Don't even think about copying that setup.