Paul the way I designed mine for the restaurant was by combining a coffee bitters we we're doing for the cocktail bar, ground/mildly roasted coffee beans steeped into the milk overnight and the darkhan from nespresso.
The three combined gave me the punch, the subelty and the aromatic notes that only a bitter can extract from the coffee beans.
Coffee is a world so extense that turning it into an icecream is very amusing because to be honest, is there even a right answer when designing a coffee icecream?