ikonos

I think demonoid (ignoring all questions of its legality) already does Oink-2.

It has a huge incentive for users to behave (I wonder if this would work for HN too):

+ registration is for free, but you need someone to invite you.

+ if you do something that causes you to get banned, the person who invited you gets banned, too. Makes people think a few times before doing something stupid.