Call me crazy, but I have been using a multiple speaker solution using AirPlay and iTunes on a Mac for more than 10 years now. The setup consist of 2 AirPort Express units, each connected to a stereo in a different room, and 2 Libratone Zipp speakers in two other rooms and, of course, a Mac. That used to be a PowerMac G4 Cube, but recently I switched to a somewhat younger Mac mini 2009.
I’ve ripped all my CD’s so I can now listen to them, or to internet radio, anywhere in my appartement, all controlled from the Remote app on my iPhone or iPad. I can also control the Mac remotely from my iPad or another Mac in my network if needed, to rip a new CD or install/update software for example.