That's the line you need to start with when you go before the judge. It becomes so clear now (to me, anyway).

Tell the judge very simply that you agreed to design his web site for such-and-such, then show him the e-mails and the work you did. Then tell him things went south after your refusal to go along with his shady deal, and here you are with X hours of work and no money to show for it. He refused to pay you out of spite, so you withheld the final product. End of story.

Hopefully the judge will see the light and tell the guy to pay you and then he gets his site.

And, from now on, make 'em sign a contract that spells out exactly what the compensation is and what the deliverables are, AND that you retain all rights in the work until payment is received in full. CYA.