I used a fretted fiddle on a lot of the Cobbers recordings as it had a better sound in the studio than my stage fiddle. I use it these days a lot for sessions and it makes a few heads turn. The one I have is a Manby made in Australia by the Manby company who were based in Melbourne and London. Apparently they had a big factory in Melbourne (Australia) and during the 1920s had the highest production of violins in the world. The fretted model was produced for learning and they made a whole range of professional models, some I've seen were excellent. The trick with the Manby (or is it Mamby?) is that the "frets" are actually grooves so you can still get the slides that you would expect on a normal violin but you can feel very easily where the fingers should go. The only disadvantage is that they are a bit heavy on strings. They seem to turn up fairly regularly in Australia so if you really want to find one, that is the place to try.