Sounds like quite a trip on the Skagit - are you going to post an Ed Ward report (as in what he was like as a guide)?
Anyway, I think I remember seeing some Ostrich feathers in the Quality Fly Shop (Port Angeles, WA). The shop specializes in hard-to-find feathers and furs and have a really good selection. I don't have their # handy - will email you when I find it.
Also try Anglers Workshop in Woodland, WA. They have a lot of exotic flytying stuff and, even though not a fly shop, are a good source for materials.