That technique does work well, I've used it too. Get's you started in the right direction. I'm a 97-03 guy (since I own one) so I'm not sure if the 04+ style has the integrated parking brake, or the shoes inside the rotor hat style. Either way try to make sure the piston being seized is the cause by making sure the parking brake isn't somehow jammed on from rust, debris, etc. I know you said its out of the question, but that would mean you already took the wheel off and checked.
Unfortunately rear calipers are more expensive. Rockauto shows them to be around $100 each, largely due to the core fee though. I've never done core's on rockauto before so I don't know how it works.
