I must say that I really do not understand your question.
The whole point of a laptop is that it does not rely on an external display, mouse and keyboard.
I believe the whole convergence thing in phones is much overrated. In my world, whenever I am close to a monitor, mouse, and keyboard, a PC is most likely attached to those anyway. There is simply no need to bring my own (less powerful) computer to them to be productive.
IMHO, a portable computing device makes sense only if it is self-sufficient: It's task is to allow you to be productive precisely in the case you are far from