Here's a very interesting animation about a multi-touch GUI proposal that places app windows on a long horizontal strip with sideways titlebars a bit like flwm, but app windows "tiled" side-by-side:
http://10gui.com/video/I've thought about making a new WM or a variation of flwm that does vertical app-window tiling... but maybe this could work better. Of course, you need a big touchpad to do the two, three, and four-finger gestures, but at least some types of gestures could be emulated with a traditional mouse movements and mouse keys and/or keyboard keys.
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Mike L.