Jeff,
If you go to the index pages at the bottom of this page and go to page 26, you should find a post from Kevin Cook listing all the San Juan cars, where they are now, if they still exist, and the disposition of the others. I don't know anything about the Shavano cars but the SJ post is interesting.
I believe the Friends (C & TS) are planning to restore as many as possible. Two RPO's are in Chama now awaiting TLC and I believe seven passenger cars are still being used, four on the D & S and three at Knott's Berry Farm.
I'm certainly not the expert but just happened to have printed out a copy of Kevin's post in May.