Have you tried Homesdatabase.com? or if you can google a specific address and it may show up if listed with a brokerage firm, better yet, try the website below an see what you come up with. I will be more than happy to point you in the proper direction. Agents sometimes are aware of properties that are "upcoming" or "pocket" listings where the Seller does not want to advertise. You should try an Agent.
Hope that this helps.