I sure can't find one. The standard keyboard shortcuts : Ctrl+Esc, Esc will
move the focus onto the taskbar but at that point the old controls
(restore, move, size, minimize/maximize and close) are the only things
available. A handy sequence if you've accidentally resized the taskbar to a
tiny sliver and can't grab it with the mouse or have lost a window off the
edge of the screen -- but not handy for the vertical tiling option.
Sounds like a job that needs a third party program: one of those that can
assign tasks to specific keys or key combinations.
