If you remember the last post regarding flavor drops, you'll see the Tipsy Bartender making a nice Peanut Butter based cocktail. He uses some Capella flavors, but does not go into any major details. I think Everyday Drinkres aka Common Man cocktails has a better description for the taste, comparing flavorings with the liquor, and all of that.
Check out a full length review of some Capella flavors. I'm sure they will start building cocktails with those flavors soon.