Holy cow! I found an awesome article at http://www.fastcompany.com/magazine/97/under-armour.html about the rise of Under Armour and how the company & founder have driven (and handled) the growth of the company.
There is a lot of good information here about being a small company that comes out with a product that becomes unexpectedly popular. It can create a major shift in perspective as the company grows, and in the meantime there is the issue of what to do when the big league players notice your success.
Some very interesting stuff . . . . .