HI - James P. Ambruso makes the best drapes around for Airstreams and while they are expensive they will last and last. I have a set and they have worn well and wash nicely. They come set up with the needed specialized hardware.
You can find them here Drapes For Airstream and Argosy Trailers
If you need replacement roller shades or blinds, these are still available from airstream and you can order them from any dealer.
Good online sources for airstream parts include Inland RV, Out of Doors Mart and Vintage Trailer supply. For specific help on airstream related projects check out www.airforums.com