Swaddlebees pockets are extremely slim and neat, however they are not as absorbant as 2 part nappies and really not suitable for overnight.
Bamboo nappies such as Bamboozles or Bambineos (better than Bamboozles as you can take the boosters out) are very slim for their size and extremely absorbant.
Not sure I'd agree about the bumhugger for slimness. They aren't as slim as bamboo nappies, although they are a really lovely nappy and a great design. I love the liner they have.
I do like the Baby Beehinds birth to potty nappy as you can take out the various boosters and make it quite slim. No good if you can't tumble though as it goes like cardboard. The bamboo version should be better for this but I don't have one.
Or change your clothes :-) Cut 4 Cloth clothes are superb, and made for cloth nappies from organic cotton (and they're fair trade). However they are more expensive than supermarket or some high street stores (because they're made from organic cotton, and because they're fair trade). There are other non-organic brands such as Tinker Togs but I don't know what the quality is like as I've never seen them. I've heard they're excellent, though.
Many other organic clothing brands are now making their clothes bigger in the bum - worth checking out if you are ok paying the extra (and they're usually much softer than conventional cotton).
Or, get a babygown for overnight - they're great as they don't fasten like a babygrow and are much better for superfast overnight nappy changes!
Emma