Sierra Mist, Starry, and SS Lemon-Lime....I don't think there is enough demand.

You might want to try the drink sticks:

https://www.amazon.com/7-UP-Variety-Pack-Delicious-beverages/dp/B083XL542C

We have not tried these, but we love the cherry 7-Up variety. We use about 1 packet per 1L bottle (about 800 ml).