TransluXent is an implementation of an X Server which uses OpenGL for what would be the graphics card driver. As such it can easily offer translucent windows.
What I find interesting is the fact they used OpenGL as the backend “hardware” of the project. This abstracts the GUI completely from the underlying physical hardware and as long as there’s an OpenGL driver for a particular graphics card X could be made to run in exotic places and do strange things. Commercial OpenGL support for a lot of hardware is probably better than support for X so this is a boon!
My first thought was of a 3D GUI, where you traverse a 3D environment. Your applications live in different parts of the space. Loading an application like Open Office would be represented by a slowly advancing application. The app gets bigger and bigger as it loads (remember, this is in OpenGL, doing this in a decent card won’t hurt the CPU performance!) and finally appears to “snap” into place in front of you!
Keyboard shortcuts are simply a “run mode” or zoom. Would virtual desktops exist? Maybe virtual “application groups” instead.
Enough of that, I await the flaming comments from usability geeks that will surely descend upon me once I post this! *grin*