via this auction "Marketed as "Learning Guitars", the Yamaha EZ-EG and EZ-AG are secretly a powerful instrument for controlling softsynths!
Besides their normal MIDI messages, these guitars also send out SysEx for each fret pressed and released. This allows us to create our own performance modes not originally found in the EZ-EG instruments.For those of you interested in pursuing alternate midi controllers...
Last year Yamaha released their "EZ" series of "learning guitars" -- guitar shaped devices with a fretboard full of backlit keys (to aid in learning chords) instead of strings. While these are marketed as learning guitars, their midi controller capabilies have been generally overlooked (even by Yamaha's own marketing dept). To the best of my ability, I will try to clear that up here. First off, the good news. This thing sends out a reliable and relatively expressive stream of midi data! Your host sequencer will recieve exactly what you played, with accurate velocity, no extraneous pitch-bends and no tracking delay. Hallelujah!
There are 72 very light action "keys", laid out in a fretboard pattern (12 frets x 6 rows). They depress very easily and light when pressed (handy for cleaning up your playing technique). All keys send midi note-ons ( 28-88 ) and are triggered by both fretting the notes and strumming the triggers (a set of bars on the body, laid out in six-string pattern). 
Hidden gem #1: fretting notes (no strum) sends out a very low velocity (vel=14) note-on. This sounds remarkably realistic using the onboard guitar patches, but is worth far more when used with synths or VSTi's. By varying your synths' velocity sensitivity you can add some expressive elements to your performances. Best of all, by lowering or eliminating velocity sensitivity you can play synths simply by fretting notes (no strum necessary). This greatly reduces stray notes, and is a feature found on Starr Labs midi controllers. 
