We replaced the curtains in our '73 Excella. What was there when we bought it was old, not original, but still old and needed to go. I had the curtains made by a fellow Airstreamer who did an amazing job - I'm so thrilled with the way they turned out! At first glance you would never realize what a giant pain in the butt these curtains and tracks are - I'm hoping it's a long time before I ever have to take them off again!
I'm uploading a few pictures here and have more before and after pics on my blog ==> Art of Everyday Life » We have curtains!
And if you are looking for someone to do custom curtains or upholstery, I an hook you up! : )