My 27" Cinema Display failed completely after 2 years. Did the brief black flashes and eventually cut out to black.
Now that I have it back from repair, I have stopped using the 27" Cinema Display to charge my 2011 17" MacBook Pro. It's a shame really, this is even the set-up Apple uses in the picture on the outside of the box the Cinema Displa comes in and the feature is designed to reduce cord clutter, but, it just makes the monitor get too hot and there is no real ventilation on this thing other than Apple's belief that a mass of Aluminum, ie the back of the monitor, makes a good heat sink.
I have gone back to using the 85w charger that same with the laptop and the temps of the Cinema Display are much lower now.
I can't say for sure that will extend the life of the monitor, but, the monitor went from almost too hot to touch on the back to barely warm with this move, so, I'm gonna stick with it.
MacBook Pro (17-inch Early 2011), OS X Mountain Lion (10.8.2), 16GB, Crucial M4 256MB SSD
Almost 3 years since the purchase, and this 27" Cinema is blacking out more and more frequently. And this, without being powering a laptop (it is connected to a Pro tower). Thank you for posting -- it helps to know that this problem is identifiable.