I was thinking of something along the same lines, but adding the peppercorns to secondary for a week, with some cacao nibs. Here's what I came up with, recipe-wise:
-11 Lb. 2-row
-1.2 Lb. caramel 75
-11 Oz. Chocolate Malt
-.25 Lb. Flaked oats
-.25 Lb. Carafoam
-.75 Oz. Colombus (Boil)...