For the record, William Gibson thinks "Shadowrun" is a lame ripoff of his work. Personally, I have a policy against reading literature based on role-playing games.
A company called Ergo was making "Decks" back in 1991. Except they called them "Bricks". Festering holes in the central nervous system were sold separately.
As for using an iBook for the core of a portable desktop, the major problem is that the firmware of the iBook-series machines was severely crippled compared to the Powerbook line, limiting the maximum resolution of external monitors to the same 1024x768 as the internal screen. There are hacks to get around that, but a little googling suggests that your mileage may vary.