Saw this news story today - couple bought a house that turned out to be a meth house:
http://articles.cnn.com/2010-11-29/us/couple.buys.meth.house_1_meth-lab-home-inspectors-drug-lab?_s=PM:US

Way back in 1999 when I was moving to a large city, I asked for a Lexus/Nexis search to be done on the house addresses that I had narrowed in on - doesn't anyone else do that? Sort of like a CarFax for houses... Your library, if you subscribe to that database, might offer to do that for people moving to your area. I doubt that a Real Estate broker would want to partner up with you, since they are only going to disclose what is legally required, and after all, are in the business of completing the sale.