Well, I have been working on the neck and such. I already showed the fingerboard and the fret materials. The neck is just my normal one-piece mahogany cut for my usual adjustable neck joint. What I did with the fingerboard is fill the gaps with epoxy/maple dust mixture. Leaving them open would not work very well when fretting strings, so this levels out the surface.
For the position marker inlays, I am using the butterfly keys placed across the fills. They will be randomly spaced across the board to center on the gap fill. Here is how I routed the cutouts
I also routed the peghead, both for my logo and for some more butterfly keys, since the headstock overlay is just an extension of the fingerboard wood

Note that I have a few diviots yet to fill on the headstock. Also, the fill color is actually a warmer tan than these photos.
Another photo showing the fingerboard

I was careful to lay out the fingerboard so that there are 2 cracks at the 12th fret, allowing me to use 2 butterfly keys. The 7th fret marker also crosses 2 cracks and I have to lengthen it a slight bit so that the ends get into the ebony a bit. These are just the rough routes and I still have to clean up the corners and such
So, What do I use for the inlays?
Well, about 20 years or so ago, another archaeologist gave me some pieces of fossil whale bone that she had used in her graduate studies. It has been in a drawer in the back room all these years. it has a bit of a funkey look and should be just right.
So, that's where I am at the moment.
G