Interested!
This has some of the same qualities as Slashdot, where you tag one of several reasons on your moderation.
EDIT: I just thought of a more user-directed mod/metamod system along the lines of Slashdot, but this way would be more Web 2.0. (As opposed to web 1.99a like Slashdot.)
Have a choice of pre-defined tags (about 10), each with a karma score attached to them. These tags would be long the lines of: "Funny" "Interesting" "Insightful" "Logical Fallacy" "Troll" Users could choose to either moderate a comment, which would be attaching 1 or 2 tags to a comment and thus altering the comment's visibility rating either-or meta-moderating, which would be voting on the fairness of moderation. So you could see what tags are attached to a comment and vote fair/unfair on each of them.
Now here's the rub: you get Karma by fairly moderating. (And lose it by unfairly moderating.) So while moderating changes a comment's visibility, only meta-moderating affects Karma.
Karma would be rewarded by the number of tags one could apply to a comment.
EDIT: More ideas. Users should be able to define their own tags, but only the admins would decide what point score should be attached to them!