I am waiting to take delivery of Montague's new Boston 8 which has a Shimano Nexus 8 speed IGH, and I'm considering changing it to drop bars for the extra hand positions. The Nexus & Alfine hubs use a twist shifter, so in order to use drop bars a Jtek Bar End Shifter or a "Hubbub Twist Grip Adapter" from Harris Cyclery would be possible solutions, albeit expensive ones.