I have a Diamondback Lockable Bed cover for sale. The panels can be easily removed in a few minutes or the whole cover can be lifted off by unbolting the c-clamps underneath. It can also be used to hold stuff on top, comes with tie downs as well.

fits all short bed chevy trucks (6'6") from 2001-2007
asking $700

Here is a link to pics: imgur: the simple image sharer