This is in very early stages, and no GUI is provided (only CLI tools). Source code for enumerating and switching between windows is provided (it's just Xlib + EWHM stuff). Hope this can be put to good use:

http://thp.io/2012/cyclotron/

Ideally we'd integrate this into the mcompositor swipeplugin and make it so that swiping left/right would switch between running apps, just like on webOS and BB Playbook OS. But the swipeplugin is closed source, and reimplementing it from scratch just to add this feature is not something I want to do