Hi, well they did it for 6 and 6+
I copied this little article about it. Here it is:
Aramidcore is a new technology of forming composite materials for various purposes. We put a layer of aramid fibers for reinforcement in between wood veneers, like a sandwich, and then form it by vacuum precisely to be a certain form wanted. With the aramid core inside, it allows the products can be so thin, light and also durable, and extremely strong. It does not add bulk and weights to your phone.