Inverness style rain cape

[Nanook]

I've seen tweed and barathea offered, but nothing else. Maybe I'm just not looking in the right places. Doesn't the

The once standard issue "Bandsman's Cape" for the "Highland Brigades" was not Barathea. Functional wool outerwear call for a different weave. Barathea capes seem more about dress and drama (eveningwear) than about protecting one from a downpour. Most of the ones I've seen are black.

water-resistance of wool depend on how it's treated?

One can process wool to make it less waterproof or more waterproof (for example spun or boiled) but all wool resists water. Wool fiber sheds water and its natural fats (Lanolin) provide waterproofing. More importantly: wool also insulates even when wet.