It seems like it is possible, though it doesn’t necessarily work exactly how you expect.
Instead of creating a custom panel that inherits from a predefined panel they want you to create an abstract class with all your custom info, then create a standard panel that inherits from your abstract class and bpy.types.Panel.
From one of the links (though others suggest putting the mixin class before the Blender class):
class CommonProps:
s = StringProperty(name="s",default="ABC")
class Base(bpy.types.PropertyGroup, CommonProps):
pass
class Child(bpy.types.PropertyGroup, CommonProps):
pass