Finally today we've uploaded the new Xrandr GUI to Ubuntu Hardy. I mentioned working on a tool a couple weeks ago; I discovered that Soren Sandmann was also working on such a tool and was further along, so I shifted focus to getting that tool ready for integration in Ubuntu.
The above photo shows two laptops, one connected to an external monitor, the other to a projector; resolutions, rotations, and so on can all be handled on a per-monitor basis. The projector image is hard to see since it's so bright, but it's working fine with these laptops.
This tool also has a Cairo-based graphical layout to show the screens.