This is my next bike purchase - Wahoo RFLKT - basically a head unit (display/controls) for a cycling app running on the iPhone in your jersey pocket. The RFLKT runs forever on a coin cell. The iPhone runs a lot longer w/ display off. I think I can adapt it to a wristband tool, and pair it to an iPhone running app. BUT word is that it needs a firmware revision to work well, so I'm holding off for a while yet.
Wahoo RFLKT ("Reflect") - iPhone Powered Bike Computer by Wahoo Fitness
And I think I've finally settled on the POV cam (action cam, helmet cam, etc) for me. Not quite the resolution/frame rate/image quality of the latest GoPro, but 2-3X longer battery life, waterproof w/o a separate case, LCD screen and WiFi built in, wrist control included, less dorky looking, and has a lapse-tag mode - push a button and camera records everything from -X time in the past to +X time in the future, X definable between 5 second and 5 minutes.
Drift HD Ghost | Drift Action Cameras