Don’t laugh, but with what I have available on the machine I’m using now, this is the mockup I can produce 
But before my childish doodle, some explanations:
- the left column is currently used to display the author of a post;
- on a wiky post, there is more than one author;
- consistency is good;
- from all of the above, the best place to display the list of wiki editors is bellow the author thumbnail (maybe expandable and closed by default)
