If you didnt already know it, this NAMM 2014 was pretty Keytar heavy - when I say heavy, I mean I can think of two that were released - the Alesis wireless keytar and the new Korg RK-100S.
The Korg has an on board sound engine based on the MicroKorg XL - which is a fairly decent synth engine. We caught up with Rich Formidoni who can give you the full skinny. There's also a full news item with tech details etc.
But Korg have posted this set of demos which gives you an idea of what you can do with the keytar. You'll have to imagine the shapes that the person was throwing while creating this. probly best that way.
Price $699 available Summer 2014