I spent some time building a .NET service that uses UPNP/DLNA to offer media to local devices. I got it working reasonably well, but the problem is that the client interfaces are absolutely garbage.

The better architecture is to push content over HDMI using an endpoint you control. This doesn't have to be the actual media server. We could invent a new system role and control multiple endpoints centrally. I don't want the TV to do anything more intelligent than display the video and audio frames it is receiving.