I'm going to start by checking if the wires leading into the tail light are carrying the right voltage...
... if they ARE it must be an internal issue with the integrated tail light. I was talking to someone and they brought up an interesting point that since my regulator just blew, it's possible that there was too much voltage going through the wiring (before the r/r fully burned up and opened the circuit to the battery) causing something in the tail light circuitry to blow/burn up.
... if they AREN'T, I'm not going to trouble shoot the wiring any further forward, I'm going to start completely from scratch and rewire the tail light, brake lights and turn signals. I really don't want to start tearing apart any wiring harnesses...