line-move-down-up

[A Soare]

(defun line-move-down (n)
  (let ((column (current-column))
        (line (delete-and-extract-region
               (prog2 (beginning-of-line) (point))
               (prog2 (end-of-line) (1+ (point)) ))))
    (next-line n)
    (beginning-of-line)
    (insert-string line)
    (backward-char)
    (move-to-column column)
    'down
  ))

(define-key global-map [(meta up)] (lambda (&optional n) (interactive "P")
(line-move-down (if (numberp n) (- n) -1))))

(define-key global-map [(meta down)] (lambda (&optional n) (interactive "P")
(line-move-down (if (numberp n) n 1))))