Although I won't be trying it on my next bass build, I also have dreamed of the strings disappearing into the body as if string-through, but instead angling down more like 15-20 degrees, into tuners that are routed or inlayed into place so the end of the lower bout looks clean and intact. That would be very classy! (But a bit hard to describe). But seems like what you (Michael) are envisioning as 'hide the tuners', at least from the top.
One problem I see is that on my preferred strings (Kalium, Circle-K) they really want the saddle (for strings over .098--the E and maybe the B strings) to be less than about 1 3/4" from the ball end so that the outer wrap of the string does not sit on the witness point. Not that this is impossible to solve, but it seems to me that it makes this concealed design more challenging. Also, think about string changes--getting the ball end into the claw or holder of the tuner's tensioner, if that unit is hidden inside the bass body. A good design challenge.
I would never set up a bass for myself with that thin an E string (.098 or less), so keeping the tuner and bridge pieces close will always be an issue. On my 34" scale basses I use the Kalium Hybrid balanced set with .112 bottom string and I tune the whole bass down a whole tone (D-G-C-F). Gives an even 40 lb tension on all strings. I use the bottom D a whole lot, and playing everything up 2 frets makes the bass into a short scale, sort of, like playing with a capo on the 2nd fret. Win-win for me. Sorry, off topic. But Michael, if you ever succeed in concealing the tuners inside the lower bout, I think we'd ALL love to see that!
John
