Same problem here. Fresh OS install, PRAM reset, PMU reset, nothing!
Anybody got any advice?
When I spotlight search in System Preferences for 'Trackpad', I get two options, one of them being trackpad sensitivity and the other being Turn off trackpad, but when I click them it says something along the lines of 'The trackpad option menu is hidden because you do not have a Trackpad installed!'
Really? Then what the hell am I looking at? And when I do the same search on my mac mini I don't get these options, so it obviously knows that the trackpad is sort of there...