Of all of the electronic remakes of a guitar this one looks really interesting.
http://www.misadigital.com/index.html
Using a touch screen for the right hand and a touch sensitive finger board this emulates a real electric guitar well - and I can see where a player could invoke new expressions.
Really interesting device! But (as far as I know) the manufacturer has not yet ruled on the price. And to me it 'looks' very expensive...
Some time ago a read about this one (http://www.youtube.com/watch?v=65R2FWwLp90) in a German computer technologies magazine. The price shall be around 200 US$....
Edit:
Two more videos:
http://www.youtube.com/watch?v=b-2sd4odKik
http://www.youtube.com/watch?v=PIzKH-v82kE&feature=related