I'm pretty sure Parma ham is the most famous ham produced without nitrites, although Parma ham is also jolly expensive. There are others, though.No, nitrites are what are necessary but nitrates break down into nitrites over time. You really only use nitrates for dry cures these days, especially ones that require a long hang such as salami and the like.
But bacon, mm. I think I read somewhere some Spanish guy had been experimenting with making bacon other ways. IIRC he said pineapple juice worked, except of course for giving the bacon a rather fruity tang, and I don't know whether, again, it was still just nitrites from a different source.