How about the rubber seal from around the outside of a trunk opening where the trunk closes down on it? It's a closed cell foam with a smooth surface. Some were glued on, and some were a push on over the lip of the trunk. Should be long enough from any car trunk to do what you need. Seems to me the Cadillac's had the push on type, likely get a section of it for next to nothing at a wrecker. Should be a lot of different styles if you go looking. Sniper