Don't know about using coffee wood, but if you like the idea of coffee BBQ you might try:
Fette Sau Dry Rub
1/3 cup garlic powder
1 1/2 Tbsp ground cumin
2 1/3 cup dark brown sugar
1 Tbsp cayenne pepper
1/4 cup ground cinnamon
2 cup ground coffee (espresso grind)
2 cup kosher salt
1/2 cup ground black pepper