I took the liner out of my old Ford when I got the camper. It was a mans truck and all, so I thought it would be ok/w3tcompact/icons/grin.gif Really though, my friend is an RV mechanic, and said the camper would slip too much on the liner. Also, the ribs on the liner don't always line up with the ribs on the bed-bottom. The ribs can crush, allowing the camper to loosen against it's tie downs. The liner is actually a nice container for potting soil now!
For the new Dodge, I want to Rhino or Line-X line it. It has no liner right now. It's not a priority right now though.
It is as funny idea though, to line a liner..