That's awesome, didn't know that. Cupro is very standard material though, many garments you end up with (and almost everything tailored) comes with it usually. I didn't know the WvG peacoat had the denim lining in it til I read that in this thread and went and checked; that's actually pretty cool. I had considered an oxford cloth body + cupro sleeve lining in my coat, but nixed that idea, I prefer slick linings too on coats like this. I can tell you that Mauro put a lot of money into that WvG peacoat though, that lining would've been a lot of money he didn't really need to spend, as cupro is honestly only about $1/yard and that denim lining he has is more than several multiples of that, cotton woven fabric is not cheap. I think that it really depends on what you are trying to do. Personally, I'd be rather disappointed if a brand like Mister Freedom or Engineered Garments used cupro lining in a peacoat. It would just seem off to me. On the other hand, if you are going for a fashion brand, and want to affect a very sharp, tailored silhouette, cupro (or maybe tencel) really seems like the way to go for linings.