Here's an interesting combo device: it's a foldable keyboard designed to pair with tablets to make typing easier. But it's also a cellphone, somehow. So I guess you'd always have it on you if you needed a spare keyboard?
The problem is that this phone is designed to pair with a cell-equipped tablet, so it would only work when close to the tablet. But why not figure out how to make the keyboard on a normal phone work with a tablet? Doesn't that make more sense? Ah well, this is just a concept anyhow, so it's all just talk at the moment.