It was a total pain... but I cut pieces of cardboard to size and then wrapped each one in cake foil. Slid that into the bag then the cookie and tied with ribbon. It looked really nice. Total pain. I only had to do 50 of them. I went to Kinko's and used their paper slicer because the cardboard I found was big and too unwieldy to cut with scissors. I did cut it to fit into the slicer. (My DH was having them create workbooks and I did ask permission.)
You can use a tiny dot of RI or chocolate to adhere the cookie to the foil covered board, but it isn't a solid hold. It will pop off with a little pull. But if you don't jostle too much, it'll hold for transport.
I am wondering about the waxed cardboard used with candy bars. I know it exists -- just don't know where to get it.