Here's a first take on linen. Took me a while to get the variation in thread thickness working nicely. None of the texture nodes in Poser were particularly cooperative, so I ended up with a different approach to achieving randomness. Here the thickness of each individual thread is still constant all the way through. I think that works out alright for linen although it's not ideal, but for other materials I'd definitely want it to vary along the thread as well.

-- I'm not mad at you, just Westphalian.