In an ongoing attempt to improve the usefulness of this site, I am going to add a page listing basses, bows, and other gear for sale from bass players. If you are interested in having any instruments or other gear listed on this page you can e-mail me or leave a comment on this post. I have had some people mention this as a feature that they would like to see, and it is an easy thing to set up and maintain, so I figure there is no harm in doing so. I will put the page under Double Bass Features in the sidebar once I have some listings to put out.
Be sure to include price, shipping information (will ship/need to pick up), a photo if you have it, and contact information, and I will add your gear to the list.