In the novel Fortress of Eagles by C.J. Cherryh, the word "yonder" is used like this:
... the most incorruptible, tiresome priest alive, ... him in the rope belt and rough-spun yonder.
Although it is a fantasy novel, all of the materials and species it references are ones found in real life, and it doesn't use made up names to refer to real life things, so my guess is that this is some very archaic usage of the word "yonder". However, none of my googling has found anything about the word ever naming a type of fabric or fiber.