The D4-S finally has some proper Geometry. I ended up re-modelling the whole cab haha worth it though. Should deform excellently now.
Just discovered the coolest thing ever. follow this link, then give it a few seconds to load. When its done loading click and drag with the mouse. http://p3d.in/Tt97x+spin Couldn't upload the proper textures as it wouldn't accept image based texture maps. Completely remade body, bed and doors of the D4-S to make it nicer geometry.