In my experience, I've always seen the caliper piston seals fail before a brake line. This is real obvious when it is too, but you just need to pull the wheel, and swing the caliper up to see if the piston boot is puffy (should not be of course). O'Reilly's carries these for our car in stock.

If the boot checks out, I'd say it failed where the rubber hose connects to the metal hose end, since that is what is fatigued the most.

Also, just make sure and check you don't just have a loose bleeder dino :P