Hi Diego,
it is possible to define more device types if they have an unique user agend. You can look up the user agend with a site that tells you on which browser you are or simply search for lists of devices like this one: http://www.zytrax.com/tech/web/mobile_ids.html
I tested it for the iPad and managed to get a different profile for each device. It’s not a good solution yet but I will make some more tests and write a tutorial here on how to define your own devices and user agends.
As far as I can tell, I don’t know if it makes any sense to do a custom iPad theme because every site I’ve built looked great on the ipad without customization and there is still no good solution for the “zoom” when you rotate the device from portrait to landscape. I’ll see about that.
Just wanted to tell you that it is possible despite I’m not having a how to yet. Sorry for that, but you’re not lost 😉
Cheers
Frank