Lay frame? You'll need a lot. You'll have to build a notch for the rear frame, DJM tubular control arms upper and lower, 2" drop spindles, Spohn adjustable rear control arms and pan hard bar for starters (may have to do a custom equal length 4-link in the rear). You'll then need to figure out what bags you want (2500 or 2600), custom upper and lower air bag mounts up front, and upper and lower air bag brackets for the rear. For air management, do you want auto level or self adusting? I'm guessing around $8k in parts and labor to get really close to laying frame. Probably over $10k to actually lay frame.
My old air ride truck before the suburban.
I plan on bagging the rear of my suburban soon, but mainly for minor adjusting and towing.