Thanks to my father for forwarding this article about two Savannah, Georgia, Birney bodies that have surfaced. The cars were built into a house in Isle of Hope, just south of Savannah, and were discovered when the house was being torn down.
The Savannah system was almost entirely Birneys in later years, I believe. They had 30 Birneys built by St. Louis in 1922 and another eight built by American the following year. A number of the cars were resold as bodies upon retirement in 1946. These two cars look pretty rough, probably in worse shape than the two American-built cars preserved at the Savannah Roundhouse Museum. There's also a Savannah Birney buried in a seaside cabin on Tybee Island and possibly at least one other body preserved elsewhere.
The Isle of Hope Historical Association is currently fundraising to preserve these cars, though how exactly isn't entirely clear, nor is it clear when they stand to be removed from the site of the house (or whether they've already been removed). With so much unknown about these cars, and with preservation far from certain, I haven't added them to the PNAERC list - yet. I did add them on my "non-preserved list" (one of the links on the right side of this page if you're viewing in desktop mode). We'll try and stay tuned and see what happens.