The farther you get from what the 5th wheel guys have (weight above the axle), the worse things are. It makes your setup more susceptible to sway, lifts the front more (unless you can compensate by raising your WD tension), causes the back end to sag more. About the only good it does, I think, is makes tight turns a bit easier and may save your tailgate from hitting the tongue jack.
You might look at this item:
http://www.amazon.com/Jack-E-Up-Black/dp/B00H9LLAJS
https://www.youtube.com/watch?v=dD1M-t2eqxM
I want to go the other direction, as short as I can get. I also simply removed my regular tailgate, as I have a Ram Box on my rig which has an internal gate that I can move where I want it. Also, removing the tail gate weight adds a little cargo capacity, and I am tight there.