so, I haven't read everything in this thread, but I've recently been getting in to analog circuitry myself and I've been doing music stuff with it.
MIDI Opto-Isolator Circuit I designed: http://i.imgur.com/Y9dyZ5w.png
Square/Triangle Voltage Controlled Oscillator Circuit I designed: http://i.imgur.com/JOaYo0f.png (didnt end up working cause I fucked it up somewhere)
The working prototype for the previous osc: http://i.imgur.com/wiMF2So.png
I'm currently working on a new prototype for another square/triangle using a different chip, as well as a ramp/pulse and sine, and also some PWM action for the square.
In any case, I figured I could chime in and pimp out https://oshpark.com/ cheap PCB's. Cost is based on square inch, and all of those purple pcb's in my photos were done through them, and came out to roughly 6 bucks or so
edit: also, I'm trying to go the pure analog route (except for when I hook up a midi keybaord to it. That will probably be midi keyboard -> raspberry pi (or arduino) -> voltage control -> osc. Asside from that, I'm going pure analog hooah. Which is pretty difficult apparently, especially cause I know nothing about circuits haha