I used the idea by Frank Gambale from his Album Raison D'etre. The first two strings are one octave down. So you have standard tuning and all your chord shapes remain the same only they sound different because of the octave shift. Just started this but I feel this is really great. Frank tuned the whole thing up a 4th to A like a capo in the 5th position. I left it in E just to try it and it sounded more or less like a baritone guitar. Check out this clip with Frank Gambale!