Retina MacBook Air - it will be hard to keep it thin and light

One more rumor says that Apple is working on a Retina MacBook Air. I have already done a video about that before, and I also said it will be out in Q3 this year.
But I think it will be very hard for Apple to make a Retina MacBook Air. The reason is that it is so thin and light. A Retina display is thicker, so Apple probably need to re-design it. The lid needs to be thicker, and that means that the main body needs to be thinner if it will have the same thickness as now. And what about the battery life? My beloved 11-inch MacBook Air has around 4 hours now, and a Retina uses more power so how will they solve that? The new one needs at least as good battery life, and preferably better.