I'd be interested in seeing what you can do as I'd be interested in replacing the dbus-send command with the proper python dbus commands.

Have you thought about looking into daemonising it like I do with headset-control?

Btw, replace:
os.system('dbus-send --dest=com.nokia.osso_media_server /com/nokia/osso_media_server com.nokia.osso_media_server.music.pause')

with:
os.system('run-standalone.sh dbus-send --dest=com.nokia.osso_media_server /com/nokia/osso_media_server com.nokia.osso_media_server.music.pause')