I'm just about finished with a custom fretboard for a neck I'm building. The board itself is made of black palm and it has bubinga for binding. What really puts this one over the top is the inlays. The inlays are all celtic crosses except the 12th fret. This is a celtic cross and a star that I combined into one inlay and it runs diagonally from the 11th to the 13th fret. In order to achieve this it took lots of time with a jewelers saw and needle files along with a healthy dose of patience. In order to actually inlay the board, I position all of the inlays in their position, scribe around them, then fill the scribe marks with chalk so I have a good outline in each position.
Once this is finished I use a special base designed for a dremel as well as a specialty bit designed for inlaying wood. Once the pockets are fine tuned I glue the inlay down, fill any gaps with sawdust, then cover them with water thing super glue.
Once this has driead I sand everything back flush and make sure my fret slots are still deep enough.
I'm particularly happy with how the 12th fret inlay came out. Very clean and a great effect with the star being part of it. The last thing to do is add and dress the frets.
Now that this is finished I just need to glue this on the neck and do the final shaping. Someone is going to be very happy when this shows up in the mail.