I also work in the gaming industry, as a concept artist/texture artist, but I'm trained as an industrial designer, originally, so I've always thought of new ways to make laptops more useable for gamers.
First off, the ability to input through a touchpad is very limited. There really should be a detachable, rechargeable wireless mouse in the notebook, or available as a peripheral.. one that works well
and fits the form of the laptop, without having to remove the wireless interface everytime you stow it in your bag.
A well-designed, tiny joystick for laptops would make my day too. Perhaps one that could be attached to the side or suction-cupped to the wrist-rest area? I love to play flight sims, or just to be able to fly well in a game like Battlefield 1942, without lugging my 10-pound forcefeedback joystick with me wherever I go.
As an artist, I would love to see a Wacom graphics tablet incorporated into the screen of a laptop.. one with hi-res position, tilt, and pressure sensitivity, like Wacom's current "Cintiq" like this one
tablets, but incorporated into a reversible screen, like a tablet PC.
Of course, faster response times on LCD or future OLED displays will be very nice, to get rid of the annoying tendency of the current technology for ghosting.
A GOOD pair of flat panel, folding speakers that flipped back along the screen would probably be a great addition too. I've seen one notebook that did this with a widescreen format display. It was an HP, or possibly Toshiba I think.
And finally, I would love to see a built in coffeemaker. Also a smokeless ashtray so I could smoke in my office.