The Sensel Morph is the most expressive, portable, and versatile MIDI/MPE controller in the world. It's iPad-sized, USB and Bluetooth-enabled, with hot-swappable overlays for keys, beats, percussion, video editing, typing, and generally creating the future. With 20,000 individual pressure sensors, it can detect everything from a feather-touch to a punch in the gut.
Any overlay can be turned into a MIDI Polyphonic Expression controller - and you can even make your own layouts, with different materials. Custom silk isomorphic MPE controller? Go for it! There's even an API for programmers in C, C#, Python, Max, and Pure Data.