Yup, physics are a **********. You want load capacity or do you want articulation. Pick one.
I cheat a bit with airbags in cradles in the rear and Thuren front springs, but I'm under the GVWR of an equivalent 6.4, 2500HD, 4x, crew cab, level1 trim... (which I think is 12-13k)
And no way in hell...