International Delight makes a liquid Souther Butter Pecan coffee creamer (Available at walmart) and I used it recently to go with a spice cake. I used Sugar Shacks buttercream recipe and the flavor was subtle but appropriate. I think it would work well for you because it doesn't compete. You can use it instead of water or milk in your favorite recipe.
I also noticed they have a Black cherry coffee creamer, that's next on my list to try