[PyQt] Preview skins for Designer

[Frédéric]

In the Designer documentation, one can see many nice device skins for
previewing the forms:

http://doc.trolltech.com/4.4/designer-editing-mode.html#previewing-forms

Are these skins available somewhere? When previewing in a specific skin,
is it also possible to set the screen size (very usefull for small
devices, like smartphones, internet tablets an so)?

Thanks,

--
   Frédéric