I envision a cellphone that can be docked inside some kind of a netbook shell. The phone holds all the essential hardware, but the netbook shell provides a bigger battery, a keyboard and a larger screen. Take both or only the phone with you, depending on your needs that day. And you'd never need to sync files and contacts between your phone and netbook, because they'd be the same device.

Something like this can't bee too far off.

That would be really cool! And with e.g. VNC or Remote Desktop you could run more demanding tasks off of your dekstop computer.

Or just use Bluetooth and eliminate the need to physically dock it. You can basically do that now provided you get the right phone and netbook.