Another source you might check out if you can... Colleges or your "good ol' community college". I have found plenty of nice deals posted in areas near the library or near the book store. Some of them getting rid of bikes now that they are graduating or stuff.
If you get used, get a receipt. Get the serial number checked out with the local authorities. Make sure it is not HOT. Seen someone "burned" that way.
Good luck on your hunt.