Toast had them in his truck.....http://www.jalopyjournal.com/forum/showthread.php?t=376601&highlight=ih+pickup
I remember seeing a pic of a 40's pickup in a magazine that had the roof skin of another truck welded inside the cab and finished in color of the interior. Looked really cool complete with some flea market art deco dome light.
There is an early 60's Econoline with complete wood interior, very nicely done. Can't get photos to load.
Have you tried searching the web for custom big rigs? It's not uncommon to see hardwood floors and other unique materials in some of these rigs. Just a thought...might provide some ideas.
That's Van-Go. A search will bring up a lot of photos. My wife used an Oriental rug in her '51 Chevy and found some fabric at the fabric store and made her own headliner.
replaced the headliner in my 65 newport with thin curved birch and mahogny strips stained so they'd show the grain, looked like the inside of a early gar wood runabout.