My idea would be to have a 'List of Main Authors' on each page, and have this editable by the users via a separate form, where they can select to add and remove names. People would usually be shown by their nickname, IP-numbers taken together as 'anonymous authors'.
Start by making these consists of all non-minor editors if that are 5 or more, all editors otherwise. Create an extra Special Page for the 'pages with most authors' so that we can quickly clean up the pages where this leads to 40 or 50 names.
To easily spot usage of this feature in unintended ways, let the change have a clear edit summary on recentchanges (and perhaps also on a separate logbook) - like "Authorship change. Added: John Doe, Eloquence. Removed: Jimbo Wales, Michael. After this change 10 authors."
Andre Engels