I can't even see a link, let alone open it, but I think my singlespeed counts. It started life as an '85 (approx--I bought it used) Trek touring bike, with triple crank and five-speed freewheel. I got a new roadie and wanted a mountain bike, but couldn't afford one, so I mountainized the Trek and rode it all over the Sierra near Reno for a couple of years. It was surprisingly competent, and I learned a lot from it. Eventually I got a real MB, and the Trek has been a singlespeed (took off all but the middle ring and spun on a BMX freewheel) for about five years. I still ride it on gravel and dirt occasionally, but I can't pull the hills without gears anymore.