I have a few guitars collected over the years, but my favorite is a Martin 000-15S. The "S" means it has a slotted head. It joins the body at the 12th fret. I have always thought that this kind of guitar has more tone per volumn than one with a solid head joined at the 14th fret. I was happy to hear recently that Norman Blake says the same thing.
I think the 000 guitars lost some bass when they flattened the upper bout and made the fretboard two frets longer. Blake also thinks the sound is enhanced with a 12 fret guitar because the neck joins the body at the strongest harmonic. I certainly am ready to believe it. He tends to use ancient Martin 00s, although he has a Martin "D" with a slotted head and a 12 fret neck.
The Australian small bodied Maton (about 00 size) has a 14 fret meck but has a deeper body than most 00 and 000s(about the same as a dreadnaught) to compensate for the smaller upper bout. It has a very strong bass for its size.
I got mine (000-S15S) at "Acoustic Roots" in Jenkintown Pa. I don't know if he has D15s. I was a little sceptical about a mahogony soundboard, but I think it is as good as spruce.