After extensive research (OK, random surfing while watching TV), I decided to use the free Ottobre pattern, but with some amendments of my own. The results can be seen in this rather poorly focused picture (sorry for the link, this is my first Crafster post):
I wanted to use microfleece for the part that touches the baby's bum, because it wicks away the moisture very efficiently and should prevent nappy rash. For the outer I wanted to use something cute and I found this cartoon spider fleece which fits the bill.
On the next nappy I'll:
1. Add an extra flap on outer top layer so that I can hide the elastic on the back.
2. Zig-zag the inner layer at the back before I put the elastic in.
3. Remember to add small pockets that you turn the hook part of the Velcro into when washing (otherwise it ruins the fleece).
4. Print out the pattern more carefully - look pretty large to me.
I've made a pocket or stuffable nappy, so the next step is deciding how to make the 'stuffees' with which to stuff them. My plan is to try and recycle fabrics that I already have - apparently the key is to use 100% cotton, hemp or bamboo. Not much of the latter two in my stash, unsurprisingly, so cotton it is then. Also, since I am not using a waterproof outer layer and don't want to use outer wraps (would make the spider fleece a bit pointless), I need to work out how to make the bottom layer of the stuffees waterpoof to prevent moisture wicking to the outside layer.
PS: Here's my original inspiration >>