@Leland James Tax lists are tough because every county has different reporting and they are so fluid so it's hard to maintain. In a lot of areas your best or only option is to go directly to the county. Call and ask them the best course of action.
A good alternative would be working with a list broker to get a list such as Owners with Low Financial Stability Scores (FSS) These are people who's financial situation changed since they bought the property. It can be combined with their age, how long they have owned the home, equity and other property specific criteria.