Agile Revolution relates Bob the Builder to agile and discusses the olympic stadium. All good metaphors to agile scalability. Intrigued? Read more here.
He poses the question of how large is too large... part of my response:
"When do you consider whether you should look for a new job? How about when there is a “scrum of scrum of scrums”… or even a “scrum of scrum of scrum of scrums”. At this point the organization has simply recreated an old-school political hierarchy (with the workers to far removed) within the development organization. I’m not saying this is impossible to make successful, but I’m laying odds on the fact that it will most commonly not be an agile implementation you prefer to be in over others."