I have an early 2011 MBP and a 27 inch Cinema Display. Sounds like I am having the same issue. So far, no solution.
If I unplug the MiniDisplay port cord (All Original Apple cables) from the computer, when I try to replug in the MiniDisplay Port cable - the Cinema Display does not activate. I must try several unplug-replug ins to get the Display to light up. Usually takes about 10 attempted unpluggings and replug attempts for the display to come to life.
An SMC reset - has not effect.
I am now on my second Cinema Display - My first display was replaced at the Genius bar - they said it had a defective "logic board". The second display - operated normally for about 6 months, but over the past month has been exhibiting these same problems. I still have a bit of time before the one year anniversay for the Display so the warranty is still valid. Given that this is the same issue that happened with the first display - I guess I will need to buy the extended warranty. Don't like the idea of having to pay to have this problem fixed on a regular basis.