Suppose you're traveling and your iPhone will be your primary device, and during your travels you won't have access to the internet / iCloud. But, you'd like to back it up and you don't want to carry a laptop just to run iTunes to back up. Is there a small device to backup your iPhone? I'm thinking a portable hard drive that has a layer of software to back up the iPhone and communicates with the iPhone over Bluetooth, Wifi, or direct USB connection. Anyone hear of such a thing?