I've found a few rare gems, including compilations (for single not-so-big hits from 50's, 60s and 70's) on e-bay and half.com.
Also try the following:
~ Reputable Audiophile Mail-Order Sites ~
Griffco Records
P.O. Box 8893
St. Petersburg, FL 33738
On-Line: http://www.audiophile-records.com/
E-mail: bgriffi5@tampabay.rr.com
Tel: (727) 319-3408
Fax: (727) 391-0243
Music Direct
318 N Laflin St.
Chicago, IL 60607-1006
On-Line: http://www.amusicdirect.com/
Phone: 800-449-8333
Local: 312-433-0200
Fax: 312-433-0011
Acoustic Sounds
PO Box 1905
1000 W. Elm Street
Salina, KS, 67401-1905
On-Line: http://www.acousticsounds.com/
Phone: 1-888-926-2564
Local: 785-825-8609
Fax: 785-825-0156
Tom Port / Better Records
14358 Miranda St.
Van Nuys, CA 91401-4230
Phone: 818-988-3313
Fax: 818-988-9790
On-Line: http://www.betterrecords.com/
Email: tomport@earthlink.net
Scott Taylor
17941 151st Way NE
Woodinville, WA 98072
On-Line: http://www.mfslcds.com
Email: sataylor@bigfoot.com
Red Trumpet
Red Trumpet, Inc
2101 Pennsylvania Avenue, Suite 12
York, PA 17404
On-Line: http://www.redtrumpet.com/
Phone: 1-877-733-8786
Local (717) 843-5562
Fax: (717) 843-3581
Robin Records
Lönsweg 4
46514 Schermbeck
Germany
On-Line: http://www.audiophile.de/
Phone: 0049 2853 954071
Fax.: 0049 2853 954070
These folks may even lead you to other sources.
Hope this helps.
Mike