Well........the absolute best tools for this are typically available to the professional Realtors in your area as they aggregate the data from the county assessor's office.

The information you seek is available on your county tax roles via their website but the ability to search and more importantly get the specific details about the properties that have been sold are difficult to put together.

Do you have any friends there in Tucson (is that right?) that are Realtors or have access to their local MLS to help put together a Market analysis? With a MA you can get more granular data from the assessor's website which would be the basis for your appeal. Short that Zillow, Trulia and Redfin are some of the best non-MLS sites to start with.

Drop me a PM if you get stuck and I'll see what I can do to help.