I just listened to a Radiolab podcast (Quantum Cello, 8/25/08) that featured the work of musician Zoe Keating. She is a cellist that uses a midi foot controller, a laptop, repeaters, a software program called Ableton Live and a plugin called SooperLooper to capture bits of her performance. She then weaves these recorded loops together with additional live music and creates some incredible pieces. You can visit her Web site and blog, as well as her MySpace page, to hear more of her music and learn about how she crafts her art. Check out the comments of the Radiolab blog post to be pointed in the direction of other live performers who are currently doing something similar with looping. It's impressive what technology can allow a lone musician to do.