I know of skwire's AltEdge (and variations thereof), and I wanted to suggest that alt-tab behavior be easily accesible from the touchpad region, even without mouse gestures etc. This could be done by using AltGr in combination with "." (dot) since these two keys are very easily/ergonomically accessible from the touchpad area, especially on netbooks (might also do with altgr-space, but i'd prefer the dot...).
If this is too difficult, or too error-prone, I'd also be happy if altgr-. would at least switch between the current and the previously active window.
(I did some research to find apps that might do this, prior to posting this, and also tried to, uhm, "code" on my own, but results were... very buggy... (stuck control key etc...)
AltGr should remain usable for other applications.
here's a link to alt-tab... http://www.autohotke...eys.htm#AltTabDetail