That does suck.. you already tried everything I could think of -- including the escape handle.
It does sound like your lock is hosed -- it should never spin freely.
Depending on how dextrous you feel, you could try reaching in with a long-handled tool and pushing the trunk latch/clasp to the side -- the same force the lid applies when you close it and the catch slips over the 'bolt' to lock shut. It should release the same way. I don't know how accessible it is.
I'm curious to see how your dealer approaches this.