About a year ago, I wrote this post on agency tenacity. Long story, short: Creative team comes up with a cool idea. Client loves it, but doesn't make time or money for it. The agency, knowing a great idea when they see it, tenaciously pursues it with the client until the client capitulates. Then the client ends up using it all over the place - TV, t-shirts, banners, etc.. There was never a brief or a client request. Just a cool idea and a committed agency.
Seems now the client is using it on their own products. A very cool continuation of the story.
Remember, not every agency or every creative director will take a brilliant idea and push it forward like this. Make sure you find those that will.