That is a mockup... CGI conception of what they think it will look like.
Looks nice either way.... I however, doubt it would look like that... Look at the Surface... Its flimsy... Look at the Xboxs... Non-symmetrical in all dimensions and has never been under motive to be that compact.
It is also said they will have Onlive *like* features... Where games will be pure online functioning only and will be download only. They aim to do that so people can't get their money back for DLC games.