Freelance Copyeditors

http://www.the-efa.org/res/rates.php
The Editorial Freelancers Association has a handy rate chart for ballpark figures, including copyeditors.

carlarnold@mac.com
Here is the email address of editor and copyeditor Carl Arnold.  Carl has edited books for various imprints at Penguin, HarperCollins, Random House, Holt, Simon & Schuster and Cambridge University Press, and worked as a copyeditor at the New York Times.  I've known him personally for fifteen years and can wholeheartedly recommend him.