The first step was to find out which seats will fit in the car without modification to the seat rails. In my research I determined that any seat from a 1992-2011 Ford Crown Victoria, Mercury Grand Marquis, or Lincoln Town Car would bolt in, but you have to take certain things (like side airbags) into consideration if your car is a 2001 or newer model year. This site
has any information you could ever want about swapping seats between a Panther-Platform car and was my primary resource during this project.
After I figured out which seats I could use, I started looking at the local salvage yards. I found them at the third place we tried, the Nashville Pull-a-Part.