Since the device in the video is nothing more than a reference (ie. development) platform it's unlikely that shipping devices will look anything like this unit. Much of the weight might be taken up by the battery if the power consumption of the new Intel CPU isn't brought closer to an ARM CPU (I've heard that ARM CPUs tick over using mili-watts of power while the lowest low power Intel CPU ticks over at about 4 watts...)

Hopefully the shipping devices (from who remains to be seen - Asus? Samsung?) will be smaller and similar in size to the N800, and a 770-style hard cover would be icing on the cake!

I'm not sure Nokia will switch from ARM to x86 any time soon - they can build the N800 at low cost because many of the components are already used in Nokia smartphones and thus purchased in vast quantities at low cost. Since Nokia don't make any devices with the upcoming 45nm x86 compatible CPU (I understand it's not the full deal and is somewhere between a Pentium M and Core CPU) their costs will increase and x86 may not be compatible with some other standard phone/IT components, further increasing cost. Then there is the software and emotional cost associated with changing platform...