I keep saying it: Three speeds are what fixie-riders ride when they're not riding fixed. I know the hubs are heavier and three speeds isn't that many, but honestly, high, medium, and low is all you need. Lace a good Sturmey-Archer to your rim of choice, throw it on your favorite road frame (or track frame w/ brake holes, if you prefer), and enjoy the whole multiple-speed thing while preserving the blingy, clean chainline, bike porn action you can't do without.