Until I just googled it, I didn't realize that the Diablo Sandwich probably originated in Smokey and the Bandit (I assumed it preceded the movie). Apparently, Jackie Gleason improvised a lot of that scene. There's an article about the Diablo Sandwich here. It mentions that while the Old Hickory House at Forrest Park (as seen in the movie) closed years ago, there is still one in Tucker, GA. While a couple of cheeseburgers and a glass of iced tea cost the Bandit "dollar and a half" in 1977, the cheeseburgers are now $6.29 each with a tea at $3.58 (that's $16.16). The Diablo Sandwich is $6.99. The Old Hickory House website is here.