Elliott at www.austinbikeblog.org writes,

For those of us who like both the general design of road bikes and internally geared hubs, our options have been few and far between in recent years. While Shimano’s 8 speed internal hubs are the same width as most road hubs allowing easy installation on road frames, the shifter systems developed for these hubs have been decidedly anti-road bike with trigger or twist shift systems designed to go on mountain bars. There have been work arounds for internal hubs on road bikes, but they have been inelegant to say the least.

Read more from Elliott about Shimano internal hubs.