I bet there are people working on this(nt).
I know bavsound is working on an aftermarket amp according to there
web site , for 06 and later. If there is one way communication to the amp from the head it
still might be possible but if the amp communicates status or anything back to the head unit via the bus it will be much harder . In the case of the one way communication there is still a chance that it could be done with fiberoptic to RCA conversion device.