Seems this thread ended in 03 and it's now 07 - so everyone is probably dead.

Never mind. I just want to point out that a fretted fiddle doesn't make much sense. Violins are tuned to fifths - not to octaves - and they have to be tuned by ear and electronic tuners are not correct for them. Electronic tuners are in equal temperament tuning and a fiddle is in Just intonation. The notes a fiddler plays by ear are based on both harmonics and ease of fingering - and so they play Pythagorean intervals - of around 90 cents for a half tone and 204 cents for a whole tone. This makes the instrument sound great. It also means that the position of certain notes change as different keys are used - and so frets just wouldn't work. Most people make those changes intuitively without realising it. Sometimes - to be in tune for double stopping the Pythagorean scale has to be abandoned for Just intonation ratios that give better consonance (sound better). Frets would make all of this impossible and seriously limit the musician. A fretted instrument would have to be tuned in equal temperament - and this would not permit the instrument to resonate correctly.

Basically - learn to identify Pythagorean scales and you will play in tune without frets. It's easy.