It is now confirmed,the standard for PCI Express 3.0 will not be ready in time and there will be a few months delay before it is finalized. The problems are related to the safeguarding compatibility between this new standard and the two preceding, which is a very important point.
In addition to the doubling of the bandwidth, this new standard will pass the data in 128 bits + 2 bits of control instead of the 8+2 bits.