LOL----Closest thing I ever saw to that was when I was stationed at Ft Hood (1971). It wasn't near that big, but it was a huge cheeseburger. It was at a "Drivein" (order from the outside speaker) place, and the sign said Elvis used to stop there!
The bread was one of those big round (disc shaped) loaves. Just sliced it in half and removed some of the bread from the inside so it wouldn't be as thick. I got it from a grocery store called Whole Foods.