i'm wondering if there is a way to use wp_list_authors to list only the authors with at least five (or even more, but anyway more than just one or two) published post in the blog.
Actually I don't see any "arg" to do that.
Hacky way of doing it:
This will return the User IDs of the Authors with 5+ published posts and orders them descending, by post counts. Don't think wp_list_authors supports what you need but you can always roll your own :)