All i know is that they can easily debut it by the very end of this year or start of next without running any major losses due to the existing S class..
But i belive they will show it in 2012 september at one of the big european autoshows.
And probably the first deliveries would come by the start of next year.
But like i said they can easily push it to..debut around new year..and delivery starting summer 2013
I hope they release it ASAP..( just cause i want to see it)haha
PS
Obviously that spy pic is of a normal SWB W222..not the 600.
The 600 will appear 2 years into the life of the W222..so you wont see it anytime soon