i think the leaf packs are on top of the axle, so do a flip kit and you'll get some drop there. as for the front, contact either djm or belltech; i believe they sell some sort of lowering kit. can't remember what's in the kit, though.
ask belltech if a flip kit will work for the back. it may or may not, i'm not sure. are your leaf springs above the axle? if not, then flipping the leafs would raise the truck. if you get lowering shackles and hangars for your leafs, you should get 4 inches or so out of it