"Ridiculous NAMM News: Football Helmet Guitar" -- I confess it, I'm only pinning this to have a football photo for the board cover. It also comes with football-shaped guitar picks! Click through for a funny, snarky post.
Yamaha's Silent Guitars have piezo pickups as well as high quality digital samples of acoustic guitar strings. You can play the sound through headphones or line out, and power them using batteries or its AC adapter.