Prior to Mavericks, one could reverse the direction of a Magic Trackpad, using the following defaults
commands, and magic five-finger gesture to reorient.
defaults write com.apple.trackpad.orientation TrackpadOrientationMode 1
sudo defaults write com.apple.MultitouchSupport ForceAutoOrientation YES
You can find more information here and here. Unfortunately, this doesn't appear to work in Mavericks. Does anybody know a modern incantation to bring back the old magic?
NOTE: this is not the same as reversing the scroll direction. It completely reverses all input and gestures on trackpad.
UPDATE: I got it to work. Ray Shan's "reboot the trackpad" might be part of the magic. Also, five fingers + hard click seems to be crucial to activate.
10.11.5
. Tried the 5-finger hard click before reboot and nothing happened. Turned off the trackpad, then turned it back on, still not; then did 5-finger hard click and it worked. So... (1) execute 2 commands, (2) power cycle, (3) 5-finger hard click. ... Of course I don't know if the 5-finger hard click before power-cycling was necessary. I assume not.