Dr. Pepper has just created a new CHOCOLATE-flavored version. But they're not selling it in stores. At least not yet.
It's called Dr. Pepper Fantastic Chocolate, and you have to create a "Pepper Perks" account for a chance at it. Then you scan your receipt for other Dr. Pepper products you buy. And once you have enough points, they'll send you some.
It doesn't look like you'll have to buy much Dr. Pepper to get it though. You need at least 100 points, and it sounds like you get that many just from buying a single two-liter. You can find out more at EarnRewards.com/DrPepper.