How about Sunday Drop? It was invented in New Haven, Missouri. About 12 miles west of my home town of Washington.
As a kid we always drank Sun Drop in a glass bottle. Ice cold. I know it isn't sold everywhere. Mostly midwest and some southern. I know they did a national campaign some years back with Snoop Dogs "Drop it Like it's Hot" as its theme.
It has more caffeine than mountain dew and a stronger citrus taste. I really haven't drank it much over the last 20 years, but now and then I still grab one for the nostalgia.
That experience when I was young, walking to the country store and getting it out of the cooler....awesome.