Abstract model class in django, but with table
You could try returning None or raising NotImplemented in __new__ in the class, I don't know if that would affect anything else but its worth a shot.
In Django, if I do an abstract model class, and then have actual derived classes, only these classes will have an associated table, and the abstract class cannot be instantiated by itself. If I remove the abstract=True meta information, then an actual table is created for the base class, but doing so allows client code to create an object of the base class. 
Is there a way of forcing client code to always instantiate derived classes, while having a table associated to the base class ?