If you'd like to start learning a different acoustic instrument, why not start with the mandolin? At Graham Nunn Guitar Tuition, I offer a beginners' course. This includes playing single note melodies and learning different ways to articulate notes. You can play these over a backing track. I also teach basic chords.
I started playing the mandolin after I saw it displayed in a shop window. I used some guitar techniques to teach myself how to play it. I've also learned by watching and playing with other mandolin players at local folk clubs.