[elihu]

Incidentally, a just (non-tempered) guitar fingerboard might look something like this:

http://jsnow.bootlegether.net/cbg/fingerboard_at_a.svg

I swapped fingerboards on an old Harmony Archtone with one based on the above design. Admittedly, 20 notes per octave may have been a bit much; it's kind of awkward to play. The next one I do will be simpler. Sounds nice, though.

[gnaritas]

Just remove the frets, problem solved.

[elihu]

Fretless is difficult to play accurately, especially for chords. Also, you get a louder sound from frets because your fingers aren't muting the strings quite so much.

[gnaritas]

Of course, but it does solve all such intonation problems.