One can purchase PCIe-based add-in cards for desktop PCs right now - the ASUS U3S6 being a prime example - but the situation for laptop users isn't as rosy.
Buffalo Technology reckons there's a gap in the market for a USB 3.0-to-ExpressCard/34 adapter and has introduced such a device on its Japanese website.
The IFC-EC2U3/UC, costing around £40, slips into the ExpressCard slot on most modern laptops, which then communicates with the underlying core-logic via a PCIe x1 interface.
It's a handy alternative to, say, eSATA, and makes sense for folk who frequently use hard-drive caddies and need to move masses of data around in an expedient manner.