"Wrote " とミニバッファに表示されるのがウザいので、以下
の方法を試しました。write-region 自体が呼ばれないようで、うまくい
きません。どこが間違っているのでしょうか？

;;;
;;; 方法１
;;;

(require 'cl)

(fset 'original-write-region (symbol-function 'write-region))

(defadvice recentf-save-list
  (around no-message activate)
  (flet ((write-region (start end filename &optional append visit lockname mustbenew)
	 	       (original-write-region start end filename append 'nomsg lockname mustbenew)))
    ad-do-it))

;;;
;;; 方法２
;;;

(fset 'original-write-region (symbol-function 'write-region))

(defun my-write-region-nomsg (start end filename &optional append
                                             visit lockname mustbenew)
  (original-write-region start end filename append 'nomsg lockname mustbenew))

(defadvice recentf-save-list
  (around no-message activate)
  (unwind-protect
      (progn
	(fset 'write-region (symbol-function 'my-write-region-nomsg))
	ad-do-it)
    (fset 'write-region (symbol-function 'original-write-region))))