Like the 1x1 - interesting fixed cog, by the way, where did you get it from? I've been wanting to try a fixie, but wanted the chance of bailing to a single cog if it all got too much. It looks like it bolts onto the disc mounts, is that right?
Could be just the thing for my (slightly more old school, but not much) DeKerf single speed, the wheels are built on Hope xc hubs, and I'm running v's, so I've got a disc mount spare!