Power Kinect from laptop (or another mobile power source)
Instead of trying to find 12V in a laptop (you may not be able to do it), how about buying a small 12V sealed lead-acid battery? Get a battery that is just big enough so it lasts the same as your laptop and you're set.

The battery when fully charged can be up to 14.5V (if just off a fast charger, 13.8V if charged by slow charger), so you may need a low drop voltage regulator that bypasses itself when the voltage drops below, say, 13V (I do not know what is the maximum power supply voltage for Kinect).

As for the videos - the AA battery pack is shown in the video. 10 NiMH batteries give 12-14V total.