AirPlay over unicast DNS-SD. Anyone got it working?

I've gotten this to work, but the method wasn't pretty. Because the multicast address for airplay is subnet local -only- it can't be propagated as-is by a standard router. I ended up setting up Avahi on a Linux vm with interfaces into each required subnet. Avahi was, in turn, configured for service reflection (enable-reflector=yes). This allows the daemon to gather the various mDNS requests and propagates them into the various connected subnets.

I'm not especially a tremendous fan of this solution, but it does work for a dozen or so VLAN's without too much drama. The moral of this story is, unfortunately, that these protocols are, at best, problematic.

Apple apparently made sure Apple TVs don't work with unicast DNS-SD as "a concession they made to content providers and that no amount of DNS records or search domains would allow the Apple TV to be contacted/used from another network." So you're out of luck, unfortunately.