This past weekend I met a purebreed Bengal cat at a shelter. Absolutely gorgeous and must have cost someone a fortune. They left him behind in their apartment after they had financial difficulties.

Have you tried the Northern California Siamese Rescue:

http://cn.siameserescue.org/

San Francisco Himalayan & Persian Rescue:

http://www.persiancats.org/

National rescue for Russian Blues:

http://purebredcatbreedrescue.org/russian_blue.htm

You'll still get a purebred cat and continue to support rescue. My Siamese came from a local shelter.