The idea is good - but the problem with a go anywhere chord book is that most people these days are either carrying a mobile phone that can connect to the internet, a PDA that can connect to the internet or a laptop that can connect to the internet - all of which could look up chord charts. I just can't see any serious players learning chords this way because for me its not just about learning the chords as notes or charts but as musical phrases. To me this is not an instrument. Its a half hearted measure. You're better off making an instrument that can actually be played by people travelling or away from their
guitar rig, otherwise Id personnaly prefer to sit with my real guitar at home or rehearsal learning chords as part of your playing experience. Your invention is a bit like learning the mathematics behind structural engineering without ever visiting a construction site or learning a foreign language without speaking to anyone.
Look at the market - there is virtually no decent travel guitars, yet many guitarists travel. There's your gap for success.
If you want a portable tab and chord guide, design software people can use with their existing electronic devices... honestly in the 21st century Im personally overloaded with devices, adaptors, memory cards - even my sony ericsson phone has a chord chart included that's half decent and a free application. Why would I pay money for yet another gadget that needs batteries and cables? Id rather something that enhances what I have or works as a stand alone instrument. Im not trying to have a go, just my two cents - it sort of reminds me of ab crunch machines that promise to loose you weight and end up in the garage with the snorkelling masks and steak knives. The only way to loose weight and get fit is the good ol hard way of hard work. The only way IMO to learn chords and importantly their application/articulation to your own musical personality is with hard work on a real guitar where you can fingerpick, strum, solo etc.