Can you overlay it on one of those metal “slap bracelets” from the 80’s?
Embed plastic fiber-optic strands connected to RGB LEDs, controlled by a Nordic nRF51822 or similar. LiPo + inductive charging or a magnetic connector like Apple/Pebble use? Magnetic connector for programming, + rechargeable coin cell?
Would also be cool to embed sensors in the band: Accelerometer, Pulse, Microphone, Temp.