I've always wondered about the possibilty of a multi-speed (3 at most) fixed. Sturmy-Archer (sp?) made a fixed three speed hub back in the day, but that's probably harder to get than these chainrings. How about a flip flop hub? you can put a 25er on the otherside, and use one of those surly tensioner jockey wheel thingys to deal with the extra slack....dunno, just some ideas