Yesterday I committed code which adds a semblance of tiling to kwin. Every time you launch a window, it will be maximized vertically, but each window shares the width of the screen equally. You can check out code from KDE svn. The location is /home/kde/branches/work/kwin-tiling/
You'll need to edit $KDEDIR/share/config/kwinrc and set Placement=Tiling.
Then you are ready to go.
Right now there are no configuration options, no key bindings, nothing! Still a long long way from a functional release.
Please leave feedback and bugs.