Samchillian: Tip Tip Tip Cheeepeeeee
http://samchillian.com

The Samchillian Tip Tip Tip Cheeepeeeee (patent #5,565,641) is a computer style keyboard MIDI controller based on changes of pitch, rather than fixed pitches. This scheme gives the performer the ability to perform extremely quick, rhapsodical lines. There is a software-only version for PCs.

C-Thru Music: Axis
http://c-thru-music.com

The obvious difference between this and other music interfaces is the key surface, which gives you a geometric overview of musical harmonies. Learning it is absorbing, and using it is inspirational, and fun. The layout of notes on the keysurface helps you expand your creativity and productivity in a live or studio situation. Playing it is like no other instrument.

Haken Audio: The Continuum Fingerboard
http://www.hakenaudio.com/Continuum/html/overview.html

The Continuum Fingerboard offers realtime continuous control in three directions for every finger that is placed on the playing surface. The Continuum is compatible with any MIDI synthesizer, sound module, or sequencer. There is additional MIDI communication with Symbolic Sound Corporation’s Kyma Workstation through Firewire.

Yamaha: Tenori-On
http://www.global.yamaha.com/tenori-on/what/index.html

The TENORI-ON is a unique 16 x 16 LED button matrix performance instrument with a stunning visual display. By operating and interacting with the LED buttons and the light they produce you gain access to numerous performance capabilities. There are six different performance and sound/light modes, and these modes can be combined and used simultaneously for rich, complex musical expression. For DJs & producers it is a unique performance tool enabling them to perform using MIDI and load the TENORI-ON with samples to 'jam / improvise' within their set BPMs.