Tip for searching for old models.
Recently i discovered that Goodwill Has auctions that you can bid on model kits. I have found some old out of production models like Revell 1/32 F/14 Tomcat with rubber tires, many older monogram kits etc.
There are quite a few aircraft and ships on there. You do need to pay attention though as shipping costs are typically $15. You can pick them up if at a local center.
http://www.shopgoodwill.com/listings/listByCat.asp?catID=418&ending=Items