I have 2 in nappies. Check out the Pop In. They are gusetted (sp?) so you won't get any newborn poo spillage. They are osfm and are nice and trim on a newborn. I would buy one full nappy and an extra insert, because you can use the cover more than once. Alternatively if you have some prefolds then just use the outer shell as a cover.

This nappy also fits my chunky 23 month old ok too. They are very basic looking and the colours are not exciting but they are a fast drying work horse nappy.