I think Krispy Kreme's problem is that it lost it uniqueness while growing. It was part of the brand mystique to be something "hard to find". Oftem, it pays to stay small - may I suggest Bo Burlingham's "Small Giants"? It has some interesting cases. You can take a look at the site of Peppers and Rogers, too - they have plenty of cases, with the "before" and "after" they went on and solved the problem.
I think british SilverJet is a case of a company that grew too fast. It's a pretty new airline, with more than 80% of seat ocupation, and already closing its doors.
And, of course, the most out-of-scale, mindblowing fast growth known to man: not a company, but a city/emirate: Dubai.
As a business writer myself, I follow everything Sheik 'Mo does with certain guilty: I am amazed, I want it to works, I pray for it to work.
But the practical guy in me says "It won't".