> Haven't figured it out for emacs yet.

Up until today I'd been using

  (global-set-key (kbd "C-c RET")
                  (lambda () (interactive) 
                     (set-frame-parameter
                      nil 'fullscreen
                      (when (not (frame-parameter nil 'fullscreen)) 'maximized))))

, which just makes the current frame maximized. A quick search turned up [0] which seems to give the desired effect of pre-lion "fullscreen" (hiding the menu bar and taking up 100% of the screen).

I've tentatively switched to it for now, although I noticed some weirdness when I got a message saying that I could run M-x toggle-frame-fullscreen by pressing f11: when I hit globe-f11 the resulting frame/window configuration sometimes ends up being mostly black. When I use M-x toggle-frame-fullscreen, it doesn't have this behavior. [0] https://stackoverflow.com/a/20429390