Biscuits and (pork) gravy shows that pork and milk go just fine together since the gravy is a bechamel with milk in it.

Poking around online, I do see some non-traditional red-eye gravy recipes that also add milk.

Bacon and chocolate is also a well-established pairing.

Honestly, assuming you can deal with the oiliness, I think bacon flavor would work great in a coffee drink.