PC World has an article about the top products that were announced but never made it to production:
The tech industry has had more than its fair share of products that infamously failed to take off. Some fit the classic definition of vaporware, and were all hype and no substance. A few were simply too far ahead of their time. And others were merely victims of bad judgment about what users wanted. Here are the 15 best examples of products that never saw the light of day (at least in their originally intended form), plus some honorable mentions that we just couldn’t ignore.