Brake lamps aren't rocket science and you could rewire the entire circuit in a lot less than 40 hours. Aside from being LED's, the brake circuit on your G35 is more straightforward than most. There are 7 components, the Fuse Box, the Pedal Switch, the Shift Lock Solenoid, the ABS Controller, and 3 Brake Lamps. The problem has to be power where power shouldn't be, so you need to narrow the candidates as to where it's coming from. I don't know what you used to check the pedal switch, but the right tool is a test lamp. With the connector loose, you should have battery power on one side and no power on the other.
If you get power on only one side, there's a problem with the switch even if it looks okay. That can be either an electrical or mechanical issue, so first make sure you don't just have a missing actuator button or some silly misadjustment. If it looks okay mechanically, use the test light on the cold-side wire while manually working the switch. If the switch is bottomed and you still have juice on the cold side, the switch is shorted internally.
If you get power on both sides then there's a short to 12V someplace downstream. Leave the brake switch unhooked and start disconnecting the remaining 5 candidates one at a time. Start with the lamps, they're LED and it isn't unknown for the control boards to fail short. There's also a diode on the shift-lock circuit that could melt short and allow the lamps to be back-powered through the shift lock solenoid coil. Check the cold-side wire at the switch each time you disconnect something, if the light goes out then you found your culprit. If there's still power on the cold side with all 5 disconnected, then there's a short in the wiring. In that case I'd suggest simply re-wiring the whole bus, cut the PNK/BLU brake wire at all 6 places and run new wires from the brake switch to each of the other 5. Doing it neatly will take some time, but it won't be 40 hours!