It's entirely possible that this is the case, however the weight savings over such a small amount of Alu isn't really significant when compared to the thermal benefits of Alu for heat dissipation.<p>If they were to go with carbon cases, I could imagine it a lot more if these were parts that didn't require heat dissipation properties... the lids of MacBook Pros might be a good contender.<p>Even then would people like the look? One of the things in the carbon bicycle world is that there's little point in painting carbon as the paint increases the weight and you start to lose some of the benefit... on an computer device you'd lose more in that the thermal properties would be further degraded (and carbon isn't great at heat dissipation anyway).<p>And then there's shock absorption. Carbon is great for resisting knocks, but tens to have to be engineered with directional forces in mind. Hit it in a way that wasn't designed for and it becomes more like a car crumple zone.<p>I notice on the cited patent that the corners are not carbon fiber, this is usually because carbon fiber resists sharp angles, but could also allow the corners to be made of alternative materials to help alleviate the directional force problems mentioned above.<p>Anyhow... is interesting, but not sure we'll be seeing it on all cases soon.