es-make-minibuffer-frame

gistfile1.el

(defun es-make-minibuffer-frame ()
  (interactive)
  (let* (( last-recursion-depth )
         ( frame (make-frame '((width . 60)
                               (height . 4)
                               (minibuffer . only)
                               (title . "Emacs-Minibuffer"))))
         ( enable-recursive-minibuffers t)
         ;; Runs when going down a level, or when entering a prompt. Not ideal
         ( minibuffer-exit-hook (list (lambda ()
                                        (cond ( (or (= (recursion-depth) 1)
                                                    (and last-recursion-depth
                                                         (= (recursion-depth)
                                                            last-recursion-depth)))
                                                (run-with-timer 2 nil 'top-level))
                                              ( t (setq last-recursion-depth
                                                        (recursion-depth))))
                                        ))))
    (unwind-protect
         (with-selected-frame frame
           (call-interactively 'eval-expression)
           (sit-for 1))
      (delete-frame frame))))

;; Can be evoked with
;; 
;; $ emacsclient -a '' --eval "(es-make-minibuffer-frame)"&
;; 
;; Since enable-recursive-minibuffers is set to t, it's possible to use M-x in
;; the new frame. It's also possible to execute a M-x command that prompts the
;; user once.