You might be interested in taking a look at how rusty does things on K5. He has created an interesting way of allowing the community to moderate 'root nodes' by allowing members to vote on them before they're allowed onto the front page (or into their relevant section).

Each comment can also be voted on by anyone (no restriction on number of votes), however, he recently allowed you to see who had voted what way on any comment, including historical ones (which caused a slight amount of controv.).

It all appears to work very well, and the discussions are predominately intelligent.

Pete