“The Voice currently holds the title of world’s first true chord-forming capo. Using the Voice, you can create chords and arpeggios not possible before, by simply placing the device over the first four frets of a guitar. Like an extra set of fingers, the device holds down the positions that you normally would, freeing up your fingering hand and in turn letting you create and accentuate custom chords on top of what the Voice is holding down.
In addition, the Voice helps beginning guitarists learn how to read tablature and recognize chord sounds by allowing them to form chords that their small or unpracticed hands may not yet be ready to form. Likewise, more experienced guitarists can advance their skills further by using the Voice to form a chord while they practice scales in a specified key.
The Voice capo fits all standard-sized acoustic guitar necks (1 and 3/4-inch and 1 and 11/16-inch) and all guitar necks between 1.65 and 1.8 inches.” ~Gearwire.com
Interesting idea, have a feeling it wouldn’t get big though..,