Yep, I agree in terms of I2C hardware peripherals. It certainly wouldn't be conventional to be listening to all traffic on the data line, including the address. All of that is taken care of for you by the hardware, which 99% of the time is a good thing. Now with that said, the hardware certainly is listening to any/all data on the data line, including all addresses, so if this were a part of the standard somewhere, it is technically feasible, but I have not seen this feature drawn out of the standard (if it existed) on any microcontroller I've ever used.
This is why I suspect my only recourse is a bit-bang solution, where I simply listen for any/all Master requests, extract the address and then do what I have to do to formulate the required response. It is a bit surprising that nobody else ever appears to do this as part of their test regime. I can understand for a home user, but in a commercial/industrial environment, where a would-be designer wants to be 100% confident that his design is not borderline buggy, this type of testing is mandatory.