I stumbeled onto a site that can supply most anything you want. I think it is http://www.movielead.com If that doesn't work go to PBS.org and search for Centennial the Movie. I talked to the guy and I am fairly sure that they are all Legitimate copies from Hollywood's archives.

I got
Centennial
The awakening
The Sphinx
Mandingo
Song of the South.

I hope this helps

Paul Hegge