This would be a great addition given that the XStream has a digital input along with AirPlay, Pandora, vTune, etc. I am using it with my MCA-C5, but its not directly controllable (I am using a separate keypad for the XStream) and the metadata is not visible, since I am just using the line out from the XStream into a line input on the MCA-C5.
Both are IP addressed and I'd imagine there is a fair amount of overlap given they both utilize RIO.