Don't like your chances, not that I have ever looked for it but I hope it is out there for you.

If something else does not work or you need it for originality, that stuff looks like the old horse hair carpet underlay for 70's Fords and Holdens.

Maybe one of those places that do car restos might have some from a car they are working on, as in replacing the old carpet and underlay with modern stuff.

Try an automotive upholsterer that has been around for a while, might have some thrown out the back.

Let us know what you find and/or which way you go, this is the second thread on it so it is important.

Good luck.