Hey I'm using an Aspire One too, but I'm keeping it in one piece as I use it for other purposes outside the car. Using the car charger too.
So you're going to put the One and the lilliput in the dash, and extend the original screen to the roof? I don't know if it would work that far, wouldn't it be easier to buy a touchscreen overlay kit and use the original screen as the main? unless of course it's a size problem, has to fit double-din.
Anyway sounds good, I couldn't bring myself to split open my One, at least not yet.