Wireless might be a better, make that a more reasonable option, but if you’ve got some hacking skills you’d do what this guy did: hack a Nintendo DS to act as a remote viewer and controller for a Digital SLR camera. Not only did he have to jimmy rig the hardware to connect the two device, but he’s built his own interface.
His motive you ask? He got sick of lugging around his laptop from shoot to shoot.
More shots and info here