On: Emacs as a tiling window manager

[asenchi]

This will also work without the dependencies:

  (defun maximize-frame ()
    (interactive)
    (set-frame-size (selected-frame)
                    (display-pixel-width)
                    (display-pixel-height))
    (set-frame-position (selected-frame) 0 0))

EDIT: Should've read the help :)