Make sure you file FOIA requests for the footage of the checkpoint. I'd LOVE to see the TSA produce their "evidence" of metal being at the core of the ball (they'll claim SSI I'm sure).
Not being a lawyer, the bit about the "well, you passed your drug test, so the charge we arrested you on is clearly false... but we STILL have to hold you for 12 hours" part really ticks me off--is that even legal?!
Clearly, both the TSA and the LEO were hoping they had made the "big catch" on this one.

What an abuse of authority.
(p.s. ... given the humorous circumstances of part of your story as well as the ridiculous outcome, I'd bet it will see some media interest. Please consult a lawyer first, though!)