This is the box I have. I like it. It made my truck useful. Weather Guard 674-0-01
http://www.weatherguard.com/en/view/...Chest/674-0-01
So what you're looking for is probably a chest that sits in the truck bed and does not stick up above the bed sides, and does not rest on the bed sides. This is an example of one that is bolted to the bed floor. I got mine from my brother, but I have noticed Northern Tool, Lowes, and Home Depot sell truck boxes. I believe Lowes is a Weather Guard dealer.