I just brewed a Dr. Pepper Porter yesterday. Then I found this forum today. I didn't realize that anyone else would be interested in such a crazy idea!
I just took one of my robust porter recipes and replace some of the sugars with the Dr. Pepper, and reduced the amount of hops to allow the DP flavor to come through. I was concerned about some of the DP ingredients killing my yeast, but after a few hours, it was bubbling away (I dumped in a vial of White Labs Irish Ale Yeast).
If it turns out halfway decent, I'll post the details in a few weeks.
