Maybe you don’t need a case video at all? This is what Interbrand did - they sent the Cannes Lions jury members a piece of paper and won a lion:
Interbrand | Press Releases | Interbrand Wins a Cannes Lions Gold www.interbrand.com Interbrand Wins a Cannes Lions Gold for Creating a Revolutionary Poster Experience Honoring the Life and Achievements of Nelson Mandela |