I used to live in San Diego and there are two very good used bike shops there that carry a lot of classic touring rigs. I have seen Miyatas, 520s, specialized, and panasonics there. The owner at Velo Cult goes out of his way to find good touring frames and fixes them up with all new components. They usually run around 400-500. Ye Ole Bicycle shop sells other nice used bikes but they do not tend to have a lot of touring stuff. Look them up and give them and call to see whats in stock. I think that Velo Cult has a website with pictures.

Edit: I found their website for you. http://www.velocult.com/index.php/store/
Also, looks like the prices have gone up since I visited last.