Sonic's chicken fried steak toaster sandwich. This went the way of the Dodo around here, and it seem's sonics quality went with it. Even their Ice Cream sucks now days. Now they're only good for a Cherry Lime-aid or an Ocean Water drink.
Micky Dee's Double Big Mac.
The Big Montana is still available @ Arby's, it's just called the 1/2 lbs Roast Beef (or something along those lines).
A&W drive-ins. Not many around anymore. (Chili Cheese Burger w/bacon, YUM!)
They're probably still available, but I'm 800 miles away so I'll list them here,
1. Deep Fried Chicken Gizzards at Interstate Speedway (Jefferson, SD)
2. Frito Pie at I-30 Speedway in Little Rock, AR
Old school mom and pop greasy spoon resturaunts with the deep fried, breaded, pizza burgers. When I was a kid in Nebraska, you could hit THE resturaunt/diner in most any small town, and order a Pizza Burger. It would always be a processed patty, with Mozz Cheese, pizza sauce, pepperoni, all in breading. You could always depend on it being good at filling a hole and making a turd.