SELAWD2011,
Its doesnt have to be only the calipers (for warranty coverage). I had the same issue (same model car), and after some highway speeds the left rear was too hot to even touch the rim. Took to my local dealer and they agreed to replace both rear calipers, both rotors and all pads. They did all this work under warranty since they couldnt identify if there was damage or premature wear caused by the one partial ceased caliper.
Stick to your guns with the dealer and they should do it all. However, this was last spring and it took weeks to get the caliper in stock, they claimed a shortage across Canada and the US.
Thomas