Ubuntu hacked a Motorola Atrix so it ran Android when you used it like a phone, but plug it into a dock and suddenly it became a full blown Linux desktop. That's a concept ripe with potential. Doesn't have to be Android of course, but just the idea that it's a phone when you carry it around but you can use it as a computer too with a dock with some ports on it.
Why? We're rapidly reaching the point where for the cost of the dock/monitor/keyboard/etc the additional uncharge for the processor and network card is basically zero. Combine that with cloud-storage (or even phone-storage if you have to) and you have a much simpler, more flexible solution that's usable independently.