How about this:
(defun my-breadcrumb (path) "Return path in a breadcrumb format." (mapconcat 'identity (split-string path (char-to-string directory-sep-char) t) " > ")) (setq frame-title-format '(buffer-file-name (:eval (my-breadcrumb buffer-file-name)) (dired-directory (:eval (my-breadcrumb dired-directory)) ("%b"))))
phils source share