Thankees for the feedback, but I think you mis-understood my post.

What I'm after is connecting the N900 to a portable netbook size display for use while on long journeys. Something that would fit into a small bag or suitcase pocket.
Another idea that has come to mind is: As the video out jack can be inserted/removed without shutting down the N900 (Hot plugged), make a cradle behind or under the 7" display that the N900 sits in. When a call comes in it's just a case of pull out the phone, answer and when the call ends drop it back into the cradle and it's back on screen.