I think about it all the time, but every time I take out my fixed sub-19lb Xootr Swift for a ride, I begin to have serious doubts as to how fun a ~24lb fixed-gear Nano would be.
Yeah I'm always on the lookout for a cheap(er) swift but haven't found what I was looking for yet. I decided a nano in the stable for now is better than no small-wheel fun at all!