The Sonar Axe is the latest achievement in guitar technology, allowing you to play the instrument like a guitar through the use of sonar. It reads your finger movements on the neck like playing a regular guitar with frets, but instead of strings and frets, uses MIDI to act as a controller. Maker ElectroKraft says:
"You can think of it as a combination of a MIDI Theremin and a midi drum in its operation and functionality."
That sums how you play it up. But the Sonar Axe is customizable. With options like pitch bend, vibrato, and sustain, the Sonar Axe could very well be the next incarnation of the Synthaxe. Allan Holdsworth would have a dandy time playing the Sonar Axe I'd imagine. You can check out a sound sample of the Sonar Axe here. Once you listen to it, you'll agree with the whole Holdsworth idea. You can get one of these for only $425 which is cheap considering it's like a toned-down version of the Synthaxe. Now get out there and shred.