I know next to nothing about fixed/SS, which is why I am here trying to learn, but I just wanted to say I recently saw mention in Cycling Plus magazine of the Schlumpf Mountain Drive and Speed Drive, and I found that Harris Cyclery carries them in the USA. It has one front chainring, no derailleur, and the shifting mechanism is internal. I have no idea (yet) if this will work with all frames but if alignment issues are OK then it might offer the oportunity to have a SS rear with a 2-speed front, offering a lower gear for hills and higher gear for flats areas. Anyone have ideas on this? Edited to add: It was the Dec-Jan issue of Cycling Plus.