I think i could actually make these, but it would not be easy due to the shape. Just using flat cardboard would not work well. This is actually high density flexible foam inside. I am repairing it with stuff i got from the craft store. I think they layed the foam and a piece of paper on each side in a mold and pressed it to shape as the adhesive set. I could probably lay the sheets over an old headliner and build the layers. Basically what I'm doing small scale for the repairs. I used paper bags for outer layer (note to self - get more Buster bars!) Would be a lot of work.. I did just see a thread of someone making headliners in 2 pieces. Dont know what materials they are using.