The blog Daily Guitar Repair recently shared a rather intricate project: Creating a 48 fret guitar neck. No, the neck is not four feet long—the frets are placed microtonally, at a spacing of a quarter tone each. They describe the process:
We were asked to add a second set of frets calibrated to quarter tone intervals to the existing frets. Lucky for us we have a computer controlled mill (plek) we can program to cut the fret slots.
Take a look at the modified Ibanez neck and read more right here.