Along the same lines as the Choffy.
Bolthouse farms makes a mocha cappuccino soy beverage, and a vanilla chai tea soy beverage.
I used the mochaccino to replace the milk (but not the buttermilk) in my white white reverse creamed cake (a totally neutral flavor canvass when you leave out the almond extract), then I added 1/2 Tablespoon of instant coffee and 1 Tablespoon of hot chocolate mix. The result was fandamntastic with a mocha buttercream (also made with instant coffee and hot chocolate mix.
I did the same with the vanilla chai (used the egg yolks from the white cake plus two whole eggs instead of just whites and again replaced the milk with the soy beverage) and added 2.5 tsp cinnamon, 1tsp cardamom, 1 tsp ginger, 1/2 tsp allspice, and 1/4 tsp ground black pepper. I found it a bit eggy when fresh, but a couple days in the freezer fixed that. Again, it was a hit, especially with the coffee hater in our group. I offered it as a dessert with plain whipped cream. I haven't paired it with a buttercream flavor yet, but I'm thinking caramel.
Each recipe yields three eight inch layers which rise just above a two inch pan and always perfectly level.