While guitar is the first instrument I learned, I don't play it much any more. I like the percussive sound of left-hand muting without any open strings, but playing full bar chords hurts my wrist. After years of playing rhythm mandolin I've started playing guitar again, but in drop-d tuning and only playing the three lowest strings. It sounds like this:

(youtube)

You could make an instrument that's better suited for this kind of playing. I'm only using the three lowest strings, so the neck could be much narrower. The chords are just open fifths, so they can go lower than guitar chords without getting too muddy, which means the neck could be longer. You could potentially double up the strings in mandolin-like courses. There may not be anything out there exactly like this, but if there's an instrument that's pretty close I could modify it.