There is currently a demand for lemon and lime soda, as is publically stated by The Coca-Cola Company regarding the introduction of Starru and replacement of Sierra Mist. Caffinated drinks are also more popular than they've ever been. 

In this day, early 2000s nostalgia is at an all time high and there is money to be made off of it. In every way it seems like the short lived 2002 soda "dnL", a variation on 7 Up that was caffinated and prominently cirtus flavored, was ahead of it's time. I have faith it would sell better in the current market. 

Revivals of discontinued sodas suchin recent years are always smashing sucesses, such as Crystal Pepsi, Pepsi Blue, Surge and Jolt Cola, and this seems like the biggest example that has yet to be addressed or attempted. I hope to gather a petition to revive dnL in the Generation Z energy drink-loving crowd.