# Note that this is untested.


models.py:

class Title(models.Model):
    title = models.CharField("Title", max_length=200)
    content_type = models.ForeignKey(ContentType)
    object_id = models.PositiveIntegerField()
    content_object = generic.GenericForeignKey("content_type", "object_id")
    
    class Meta:
        unique_together = ['content_type', 'object_id']


class Category(models.Model):
    def get_title(self):
        return Title.objects.get(content_type=self.__class__, object_id=self.id)



admin.py:

class TitleInline(generic.GenericTabularInline):
    model = Title

class CategoryAdmin(admin.ModelAdmin):
    inlines = [TitleInline]

admin.site.register(Category, CategoryAdmin)