[donsolo]

There's a few guitars that are 19 frets per octave and some have 32 frets per octave. This way, you can select whether you're playing a minor 3rd or major 3rd

A C# is NOT a Db even though they're the same on a piano.

Check out Hermode Tuning. That's the way they've been dealing with these issues on synthesizer. It figures out what you're playing and reintonates on the fly to accomodate.

Logic does it.