20,000 miles just hit and the driver side rear caliper needs replacing. Dealership isn't sure what caused the caliper to fail but the pads were toast along with the caliper itself. Rotor itself will also need resurfacing. (2008 Scion tC Manual)

I simply wanted to post this just in case anyone in the future runs into this problem.
Symptoms I ran into:
-After extended period of driving time, caliper gave off a burning smell similar to an electrical burn.
-Intermittent squeaking that was not related to applying pressure to the brakes themselves.
-Constant squeal/grind once the caliper decided to compress itself against the rotor 24/7.
-Going in reverse caused the loudest grind as well.

 

First I've heard of any caliper issues. Sounds like an isolated incident (hopefully).

 

Every other caliper/pad is perfectly fine which probably suggests it is an isolated incident as you said.

More than likely just a bad caliper from the factory line..

 

actually...maybe not. My front passengers side caliper is frozen forward right now. It wont retract which is in turn causing the pads to continuously rub the rotor. I just had to buy new rotors. Is this what happened with your caliper? It wont retract?

 

I'm not sure exactly what happened. I was just shown the damage when they had it up on the lift. I'm pretty sure it was aligned incorrectly from factory then the caliper within the last couple thousand miles, had issues with decompressing I believe