The shorter the neck, the shorter the frets -I mean the space between the metal frets, that is, the places where you put the fingers on.
Think about this: with the strings on air they have a given frequency and thus a given note. When you push the 12th fret you are playing the same note than the string at air, but one octave higher. One octave higher means double the frequency, and for doubling the frequency you need to reduce the string lenght exactly by half. That is, the twelfth fret must be exactly at half the string lenght. If the neck is shorter, the string lenght if shorter and you will have to put twelve frets in less distance, therefore they will be narrower.
If you look at a 24 fret fretboard, for the same reasoning, the 24th fret must be at half distance between the bridge and the 12th fret because it has to double the frequency of the note at 12th fret. I don't know if I have explained myself.
If only I would have played much more than I had...
Vinnie Moore rules!!!!!