Netgear makes a powerline adapter set with built in airplay support (powerline adapters uses the home power line grid as your network grid)
The specific model is xaub2511
Just picked up one of these units and discovered that the DAC part of the airplay functionality is a USB cable.
The cable had a bump in it which looked like a DAC cable so I took the cable and plugged it into my pc. Sure enough, it worked in my computer as a USB dac!
So I then took my AMB Gamma DAC built by yours truly and plugged it into the powerline USB port and you better believe it, it was playing music in all it's glorious wolfson DAC glory.
In summary, if you want Airplay compatibility with the ability to use your own usb DAC, check out the Netgear AV200 with Airplay support!
the Gamma uses the drivers built into the OS (windows & osx) so I'm guess this wouldn't work with DAC's that need special drivers.
Edited by moophus - 11/14/13 at 6:03am