Would it b possible, or is it currently possible to create a playlist on the upnp server for music playing devices that would present similar to the audio and simply create a local queue for the device to play through?
I have an old linksys wireless media player and it has locall built playlists, but the firmware is totally crap as is it's web interface. There's no way to make local playlists, they were originally presented to the player via the included realmedia server that comes with the device.
currently, i have a freenas machine i'm testing. freenas comes with mediatomb, and it is seen by both my htpc software as well as this media device, and reportedly, a few digital picture frames i have on the way. so far, the only limitation i'm experiencing is the inability to have the upnp server broadcast an actual playlist as opposed to simply a file list.
I did think about offerint that feature but never came to implementing it - probably because I do not use the only device that would support that anymore.
Currently you can only create virtual containers out of existing m3u/pls playlists, but you can not create an m3u or pls from an exiting container. However, I think the Intel MediaControler is capable of doing that, you may also check the Cidero control point, it has some sort of playlist support and if your linksys device can be externally controlled via UPnP, you may use Cidero to queue selected songs to play on the linksys from MediaTomb.