Yes, and I carry one around in my backpack all the time. But it's not convenient in many situations.
As I posted elsewhere:
> One of the reasons I'm excited about a built-in second screen is, I don't need to carry another extra device (second screen or iPad). I mean even if I need to use an ipad, I'm currently slouching on my couch. I need a flat surface to keep that ipad/screen at the right angle. Sounds petty but it's just very convenient to have more real estate on your lap (or on a flight or cafe table).
