Your requirements are pretty easy to meet in almost any of the 13'ers.
Budget and condition are the two key parameters- how much are you willing to spend and how much work are you willing to do?
As you've figured out, finding one is the challenge. Checking all the fiberglass classified sites daily, including this one and www.fiberglass-rv-4sale.com
, using a site like Search Tempest to track Craigslist within a specified radius, and posting wanted ads (be very specific as to size, price, features, and condition) can all produce leads.
Be ready to jump on a moment's notice. The best listings often sell in hours, not days. But be prepared to do a careful inspection and to walk away if necessary. There is an inspection checklist in the "More" tab at the very top of the screen- go to the "Document Center" and look for the "Buyer's Checklist."
Best wishes in your "egg hunt"!