This is a nice MIDI controller from Artifon. Not cheap though, 600+. Features:
Play guitar, bass, synth, violin, drum pads, and more, on a revolutionary MIDI controller
TIME Magazine “Best Invention of the Year,” #1 Instrument on Kickstarter, PCMag Editors’ Choice
The first fretted and fretless digital string instrument; low-latency, pressure-sensitive playing
Ultra Portable: Lightweight and 6-Hour Battery Life; USB & Lightning Cable iOS and Mac Connectivity
2 Stereo Speakers & Headphone Jack for creating on your own, or jamming with friends