I made this and used Wild Turkey 80 proof, 16oz. Soaked the oak cubes for a good two weeks and poured it all in the secondary. I'm very happy with the bourbon flavor and I don't think the Wild Turkey was "inferior" to something more expensive like Maker's Mark in this case. I like your idea of a little coffee though.
FERMENTING: nothing, I'm slacking
KEGGED: Innkeeper, Dry Irish Stout, Velvet Rooster Tripel, Smashing Pumpkin Ale
BOTTLED: Dubbel, Kriek