As I didn’t want to install GPlay I installed BubbleUPnP from Aptoide and realized it’s already available as an Xposed module.
This lead me to looking for a UPnP renderer. On Debian Wheezy I’ve got it working with the aforementioned Yaacc and rygel-playbin. Choose yaacc.de as MediaServer (earth globe with network plug), start Rygel Developers 0.1 and tick it as client (laptop symbol) in Yaacc.
You can also set up XBMC as media renderer by going to System->Settings->Network and tick “Allow control of XBMC via UPnP” and then restart XBMC.
Up till now I have only played Yaacc’s files (Jamendo “MP3”). What you can play should really only be dependent on your renderer. (There’s a GStreamer plugin for Rygel available; ). There shouldn’t be a reason being not able to play files.
So this works without BubbleUPnP but I don’t know if that’s applicable to streaming from other apps like Spotify. But I’ve read somewhere in the BUPnP help that it’s able do this … Look Audio Cast which may be an in-app feature (Xposed module).