The Kalichord is an electro-acoustic physically inspired folk instrument that I invented which is a cross between an accordion, a kalimba, and an autoharp (with some acoustic guitar thrown in there). The Kalichord was specifically designed to let you be a bass player and finger-style guitarist at the same time. 

Read the NIME 2009 Paper here.

How It Works - overview

The right hand notes are played by physically plucking eight small tines which function as virtual strings. The tines are made of piezoelectric film, and analog signals from the tines are used as excitation signals for a physical model of a string instrument. In this way the instrument responds to all kinds of plucking subtleties in a way that makes physical, intuitive sense and is far more expressive than a MIDI controller. 

The left hand plays additive-synth bass lines using buttons positioned under the thumb and fingertips. The thumb buttons play the tonic of a specified chord, and the finger buttons and right-hand tine-strings are constrained to notes in that chord. This allows for independent bass lines and chordal melodies. 

The two hands can also be rotated with respect to each other, which is used for additional control parameters such as octave shifting, wah-wah effects, and changing some physical parameters of the string model. The result makes playing bass lines and arpeggios simultaneously both easy and very expressive, which is an advantage for any solo performer. 

Below are pictures and a video from NIME 2009