Dose you truck even lay frame now? If not I would work on that before I did a body drop... and if it was me I would build a new frame out of 2x3 rectangular tubing and then lower my body mounts to get a stock floor body drop.
Right now I am in the process of cutting the escalade up and doing it right way. It will be laying frame but I gotta tell ya there is allot of fabrication involved. So for I have cut the inner fenders up front, I still need to raise the upper CA mounts. I pulled the fuel tank and all associated parts, pulled the rear end and shaved off all the brackets not I am just waiting for my material to come in to build the lower link mounts, lower links and notch the frame. Oh and I can't forget about cutting the floor out of the rear and building new wheel tubs.
oh and here is an Escalade with a new frame to lay on 26's