What a teaser!
I suppose you are not talking about the extended ACEs with more queues as this was documented already as a feature for upcoming graphics cards using the "GCN1.1" iteration (as well as this volatile flag stuff Mark Cerny talked about as customization and the FLAT memory model) and one could argue it is probably not so invasive to the core (okay, the flat memory accesses would count, I guess).
You can send me a PN. I can be as silent as a grave.
Edit:
I completely forgot about the additional high priority command processor for the PS4. Okay, I agree, there was definitely some customization.