Can the Potion of Life be muled to provide a character with a steady stream of +20 to life?
This question could also be extended to include other quest items that provide a permanent bonus, such as the Book of Skill. In any case, a single character cannot pick up (or get by trade) a quest item more than once per difficulty, so the answer is that your proposed scheme will not work.
Otherwise, it would be possible to continually create new characters just for these quest items and then buff up a single character for unbounded skill points and HP.