Sadly, it seems that SATA-Express won't be featured on the upcoming Z97 chipset.
A report from the Chinese VR-Zone states that the SATA-Express standard, which was repeatedly expected to come to the upcoming Z97 chipset, won't be featured after all. Based on the information available, it would seem that this change would make the Z97 chipset nearly the same as the existing Z87 chipset.
It seems that Intel had not given a reason for the cancellation, though seemingly Intel is encouraging manufacturers to implement the technology by themselves.
SATA-Express is a technology that allows devices to use PCIe lanes for higher bandwidth, and it is a way that SATA can co-exist with PCI-Express, similar to, but not quite the way as the mSATA co-exists with mPCIe.