Would it be worth having an associated searchable "archive" on the site so people can browse and use the icons/furniture and such? Tagged by style and genre. A caveat of the challenge being stuff goes into the archive for people to use (with full credit to the author of course). Although I'm not sure how people would feel about that condition.

Just a thought anyway.

But anyway I like the idea and I'd give it a try, although I'm not very good at photo realistic stuff so mine would be more of a sketch style.