Can I make the trackpad tracking speed faster than allowed in System Preferences? The title says it all ... I have the trackpad speed on my Macbook Pro Retina 13" set to the max, but I'd like to try it faster. I recall some of these things can be configured by modifying ~/Library/*plist files or somesuch. Thanks in advance for any help.
Open up the terminal and type 

defaults write -g com.apple.trackpad.scaling x


"x" being how much you want your mouse speed increased. "6" worked perfectly for me.

Simply log out and log back in and your setting will be changed!

Under System Preferences the trackpad speed will now be in the middle of its slow/fast options, and if you change it it will override your new changes.

Source was this guy: https://gist.github.com/brandonb927/3195465
Found this in line 328 of his code.

Hope it works for you as well as it did for me!