Well for those of you interested, I play around with the odd laptop and have managed to install a Mini PCI Express USB 3.0 card where my WLAN card used to be, in a Compaq CQ60 Laptop. I removed the DVD burner and replaced with a slimline SATA HDD caddy and hacked the side of the slimline case to mount the two USB 3.0 ports.
It works fine for fast USB 3.0 sticks and 2.5" cases provided you use an SSD. Mech drives don't work. I think the problem is supplying 5 volts to the USB 3.0 connectors. At first I thought I'd get the power from the mini SATA port because it supplies 3 V, 5 V and 12 V. But when I checked the voltages with a meter, they are all 0 volts. I think the BIOS only supplies power if it finds a connected device. If I could route 5 V from the motherboard then I'm certain it would work for all USB 3.0 devices.
Here is the card I shoehorned in: http://intrl.startech.com/Cards-Adapters/USB-3.0/Cards/2-Port-Mini-PCI-Express-SuperSpeed-USB-3-Card-Adapter~MPEXUSB3S2