No, I don't want to support a bunch of little patches on top of emacs.

But it's frustrating for me, too, because I want the feature as much as anyone else. I've been making do with "(setq ns-auto-hide-menu-bar t)" which is close to the desired behavior, especially when combined with maxframe [1]. It still has the window's title bar, so it's not exactly there.

[1] https://github.com/rmm5t/maxframe.el I use it like this (where super is the command key):

  (defun toggle-frame-maximization ()
    (interactive)
    (if (frame-parameter nil 'mf-maximized) (restore-frame) (maximize-frame)))
  (define-key global-map [(super return)] 'toggle-frame-maximization)