Not directly, but a very close friend is an amateur luthier. He mainly builds electric guitars. He wanted a "silent guitar" so he built a "neck only" style electric with a headphones out. He had a very interesting slotted tuning pegs in the tail piece, such that strings were anchored at the nut, with tuning machines in the tail/body - similar to the commercial ones.
So if you want design advice, I'd say, design around a "neck only electric", but then put on whatever type of strings you want. Of course, nylon strings require a microphone saddle or some such thing as they will not work with a pick up.
Good luck !
2013 Rodriguez FF Sabicas blanco
2015 Trevor Gore custom Neoclassical
- redwood top, Palo dorado B+Ss.