(defvar super-global-keys '())

(defun super-global-set-key (key function)
  "Make a super global KEY that invokes FUNCTION."
  (global-set-key key function)
  (add-to-list 'super-global-keys key) )

(defun disable-super-global-keys (&optional map)
  "Disable MAP super global keystrokes, so they can be assigned."
  (dolist (k super-global-keys)
    (define-key (or map (current-local-map)) k nil) ))

(define-prefix-command       'C-o-prefix)
(super-global-set-key "\C-o" 'C-o-prefix)

(provide 'super)