Are you looking for a panel to repair the full height of the inner bedside? If you need only the lower 6" or so plus the "L" with holes at the bottom, check out Mar-K. I bought some of theirs for my long bed and had them installed when I had the body work done. They did the trick.
Right rear-
http://www.mar-k.com/Catalog/index.aspx?LID=8901
Full set-
http://www.mar-k.com/Catalog/index.aspx?LID=8897