Portrait Display Drivers For X11?

helloRockview asks: "I have a MAG LT541C TFT, which I often use as a display for my Linux machines. Its best feature is that is has the ability to swivel into portrait mode, which works great when it's hooked up to a Windows box with 'Pivot' software installed. I'm wondering if there are any such utilities for X that will switch screen orientation from landscape to portrait on the fly." We did this question over a year ago and there didn't seem to be an answer, might there be one (or more) now?