An UPnP media controller indeed would be very welcome, it really augments the media server on our N9.

But I'm afraid I fail to see how this would provide streaming-audio-out-to-upnp-capabilities. The "GST Launch" in the screenshot could very well be a Rygel installation on his local machine. Indeed, Rygel supports streaming from gstreamer, but our N9 is lacking the library for that, as was discussed earlier. But seen his work, Jens might very well be able to pull it off