I seem to have fixed the bug I mentioned in my last post. This is what I had:

class MetaPlayer (type (QObject), type (dbus.service.Object)):
    """Dummy metaclass that allows us to inherit from both QObject and
    d.s.Object"""
    pass

class Player (QObject, dbus.service.Object):
    __metaclass__= MetaPlayer
    [...]

Notice that MetaPlayer doesn't have a explicit __init__() method; one would spect that Python would take are of that. Here's the fixing code:

MetaQObject= type (QObject)
MetaObject= type (dbus.service.Object)

class MetaPlayer (MetaQObject, MetaObject):
    """Dummy metaclass that allows us to inherit from both QObject and d.s.Object"""
    def __init__(cls, name, bases, dct):
        MetaObject.__init__ (cls, name, bases, dct)
        MetaQObject.__init__ (cls, name, bases, dct)

I really don't understand why I have to be so explicit. Maybe it's because the metaclass for dbus.service.Object, dbus.service.InterfaceType, inherits from the type type[1]; this type is a new style class[2], but doesn't inherits from object. Thus, I think, the inherited __init__() methods are not called automatically.

In any case, now I can mix QObject and dbus.service.Object, and it works fine. For instance, this call works:

$ qdbus org.kde.satyr /player quit

dbus python pykde

---

[1] the type type is of type type! here:

In [1]: type (type)
Out[1]: <type 'type'>

[2] its type is not instance but type, as mentioned above.