I have created a new structure element in the wiki whereby anyone wishing to add copyright material, providing they are themselves the copyright owner or can prove that they have the copyright owner's consent, can add pages which do not feature the Creative Commons License at the bottom of the page. Any material on those pages could also be clearly marked as being copyright.
To create a copyright page simply use category: before the page name, so a page called copyright:example would create a page called example and which would not feature the Creative Commons License. I have added a notice to the home page stating that any such pages with copyright in the url are indeed copyright.
I have also ensured that any pages created in this way can only be edited, modified or deleted by their creator, or by the Moderators and Administrators.
"One does not discover new lands without consenting to lose sight of the shore for a very long time." ~ André Gide