I know that we chatted last night about this, but I thought about it some more.
if it were my truck I would remove the bodylift, sell the tires, and buy something "stock" sized in at the most a mild AT. What is killing your MPG is the added height and those heavy as hell tires. You should be able to remove bodylift, slightly decrank keys (keep lift keys), and run a lighter tire.
I don't see the point in stripping your truck and lowering it when you can just modify what you have an get your MPG back. I mean honestly your truck would look very similar, but just be shorter (no need for amps then), be quicker, more efficient, and still look awesome.