Sugar free energy drinks
I recently found Zipfizz energy drink at Sams Club that are also mostly B12, 10 calories & sugar free. They come as a dry powder that you mix with a 16 oz bottle of watter. The grape is good. They have a website that talks more about them and the ingredients. They promote themselves as a "healthy energy mix".

Im not an energy drink drinker (unless you count Coca Cola) but I saw one of my friends drinking this
http://www.rockstar69.com/product.php?pdt=18 = Rockstar Energy drink PINK! Zero sugar, Zero carbs.
website says=
Zero Sugar, Zero Carbs! Lightly carbonated & only 10 calories per can. Rockstar Pink is enhanced with 100% RDI of 5 critical B-vitamins, caffeine, and ginseng to provide an incredible energy boost for those who lead active and exhausting lifestyles-from athletes to rock stars. Enjoy this refreshing, perfectly carbonated energy drink super chilled.
here is the nutrition label=
http://www.rockstar69.com/productIngredients.php?pdt=18