Here's a limited list of resources:

The environmentalist in me cannot resist pointing out that many woods like ebony are being harvested in an unsustainable manner. Check out this website for more information: http://www.iucnredlist.org/

http://www.woodworkerssource.net/
http://www.exoticwoods.com/ (check out their sale/damaged section)
http://www.bluemoonexoticwood.com/index1.html
http://www.macbeath.com/ (i've used these guys before and they are good!)
http://www.natlhardwood.org/