I think the thread should be locked and there should be 2 posts in the thread.. One for Signature of the Week and the other called Icon of the Week. Each time there is a winner his banned, date, theme and week number would get edited into the post..
But this would need someone whom can edit locked threads.. So could you maybe edit it when needed?
Also the SOTW post would be made by me, and the IOTW post would be made by Dukey... How does that sound?
Also if there were to be added Sprite of the Week or Drawing of the Week the thread would just get unlocked long enough for the Host/Hostess of that event to make one post in there, and the title would get edited..