Motherease AIOs (you do need to add liners though so not really an AIO) are great, available in all sizes and fastenable top and bottom.

We also have Motherease one-size nappies, DS has used them from about 4-5m old and still fits them nicely; they have snap-on-able inserts for night use. I must confess, while they don't leak and are pretty good, I don't use them too much - they are the most hard work maybe? Three-stage nappy and no velcro! How lazy am I? I love flat nappies but not working two lots of poppers clearly.