We need a concept of a non-MD video player, much the same as what we do for audio zones for squeezeboxes. This can be done, but some legwork will need to be done to create for example a DLNA media player device.
I believe niz23 wanted to work on this at some point, but life sometimes gets in the way. ;-)
With this said, it is possible to assign a dlna device to a room and be able to send MH Media Play commands to it. But it needs to be written.
There are other aspects, for example, how do you trigger the device? You would have to create a room for the device called portable devices, and split EAs up so that you could map multiple media players into the same room, etc.
This is a place for much experimentation, but first, the DLNA streamer needs to be written, and hooked into Xine Plugin. This device would run on the core, and would be talked to by the individual DLNA player devices.