DT Swiss have updated their 190 hubs with a carbon shell, and called them the "180"... which is about the weight of the rear road hubs. Available in Shimano or Campag road versions, and centerlock (QR only) mountain bike versions, the price is high enough to put off most people but if you need the best and have QR axles, you won't find anything lighter that works as well.
As always with DT, although they're light it's not just about the weight. You can bet that these hubs will last longer than pretty much anything else, the ceramic bearings will roll smoother, and they won't let you down. Just as well at these prices (£275 front, £500 rear). Buy them here now >.
Here are a couple of pictures, it's a shame they don't have any carbon showing (it's the hub shell - the central tube) but they still look pretty: