Not just another smartphone launch from ASUS, the Padfone can even slip inside and power a 10-inch tablet, should you need some added screen size.According to Crave, the phone part is a four-inch Android touch-screen phone which fits snugly into the larger 10-inch tablet via a compartment on the rear. In essence, the 'tablet' is just a display, albeit one with a front-facing camera. All the processing is done by the mini device, with all the storage there too.Still in prototype form (so don't expect it any time soon), the Padfone tablet is perhaps a little chunkier than most tablets on the market, as it has to allow room to house that phone. So if portability is a big thing for you, the Padfone might not float your boat. But if most of your tablet time is likely to be on the sofa, it's probably worth a look.On the plus side, it should work out well financially. For a start, you'll be buying both devices as one, rather than going out and buying two separate products. Also, you'll only need to pay for a single 3G data plan, rather than paying out for two. That's got to be a hefty saving.Sadly, due to its experimental nature, there are few concrete details about its inner workings right now, perhaps because they are subject to change. Although with the Android operating system due to merge for phones and tablets later this year, the Padfone looks a prime candidate to use Google Ice Cream Sandwich OS when it launches. That might give you an idea of when the Padfone will hit the shelves too.An interesting development. Wonder if Apple is looking at anything like this? We would guess not, but we can always live in hope.