I thought I’d share a few pages from my sketchbook with you all. You may or may not find them interesting!
Various ideas for alternatives to standard frets to shorten the length of a wire.
Ideas for the Dronemachine improvements.
Ideas for variations on a psaltry theme.
Sketches for the design of Simons Oak Tinjo, The Vulpes design on the right I want to include in a future build
More Dronemachine ideas plus some workings out for a pentatonic hammered dulcimer tuning (future project)
On the left just a few body shape sketches, and the right the ideas that led to the Droneitar.
Ideas for an acoustic version of the Droneitar, which is already half way built.
Sketches for John’s Psaltry
There’s tons more but some pages are even less coherent than these ones! Some instruments don’t need sketches and just develop naturally from the materials being used. Likewise a lot of sketches and ideas will likely never get turned into anything physical and just remain an idea in the notebook.
Vulpestruments 
I have seen this whole post about beautiful Sketches of different types of musical instruments. In this post you have given few body shape sketches and take more ideas for different types of musical instruments.