I don't belive there is a core way of doing this. Consider duplicating your quizzes and calling them "QuizTitle - Attempt 1" and "QuizTitle - Attempt 2", etc. You can restrict access so they can only see Attempt 2 if they have a certain min/max score on the previous attempt. Students will not be able to have their previous attempt answers copied over if the 2nd attempt is a separate quiz, but may still be cleaner than having assignment submission boxes? Of course, depends on your unique situation.