Anyone tried the newer "rolling" type capo? It has an hourglass shaped rubber back with springs that attach to a round cylindrical rubber piece in front which has a metal rod going through it. One of the springs unhooks from the rod for attaching and unattaching the capo from the guitar. The beauty of it is, you can roll it up and down the neck, even during the song if you have quick fingers. When you finish using it, you can just roll it back over the end nut onto the headstock. The springs are just the right tension so they don't pinch the strings sharp when it's behind the nut. It's great on guitars with a thick neck, but it leaves a little string buzz on my relatively thin-necked Taylor.

Just thought I'd toss that one out there.