I recently stumbled across Inspired Instruments You Rock Guitar which, in essence, is a Ztar like midi controller which can also be used as a Guitar Hero or Rock Band interface bridging the gap between virtual guitarists and real ones. To hit the ultra accessible $150 price point, the construction appears to be all plastic. Even so, since the discontinuation of Yamaha's EZ Guitar line there has been a hole in the affordable MIDI guitar controller market which the You Rock Guitar perfectly fills.
While their pre-release marketing is strongly focused on the gaming abilities of the device, I'm very excited about it's potential to sequence tracks and even perform with it. The guitar has a built in sound library sampled from a wide range of classic instruments and plans to sell additional sounds ala carte however it's real power lies in the ability to control external MIDI devices to trigger anything you could possible think of. Below is a video of the You Rock Guitar in action, be sure to watch the segment about one minute into the video where George Pajon Jr (Black Eyed Peas) demonstrates the device.