I think your time would be better spent improving your GPA and otherwise improving your application than trying to scheme ways to be a shoo in at Harvard and Hopkins.
The fact of the matter is, there's no such thing. If it were as easy as you wish it were, everyone would be doing it.
But let's say you're right, and that a Nature or Science pub is a shoo in. The thing is, you don't just "get published in Nature." Most reputable scientists who have years of experience in their field don't get published in Nature. The amount of work and effort, not to mention novel thought about a complicated process, an undergraduate would have to do to get published in Nature is extraordinary. And at that point, the Nature pub isn't the cool thing. It's the work you did to get there that they care about.
And that stands true for all applicants to all medical schools. You have to be at the top of your game if you're going to be accepted and you're going to excel. Looking for the easy way out isn't the answer.