I built this Rhino rack and did a few other upgrades for a friend who takes this to the desert every season. The new rack is bolt on and uses the factory holes in the bed. It's leaving today and I'll post more pics of other things I did also.
He recently built a stereo box in the cab, and decided to go with a deep cycle Odyssey battery.
Sits above the floor so the mat can be pulled out and the bed hosed out. The coolers will be held down with bunjee's attached to hooks that he'll be adding to the sheet metal. They are the stock ones that were in the corners where the rack bolts in now.