I just saw this guy on youtube playing rock fiddle:
I cannot see very good but I think he has frets on the fingerboard. If you want to try it with your own fiddle go to the following link:
Personally, I think fretless rocks. Another discussion about fretted fiddles:
Beside this, I really like what Ed Alleyne-Johnson does on this video:
But I don’t think he is using fretted fiddle.