The cheap chinese PCI-E USB3.1 Type-C adapter that I ordered arrived this morning and I just got around to installing it. 
First impression on seeing the card was "Fuck, that looks CHEAP", it very visibly had a cheap build quality. However, I went ahead and installed it in my system, taking up the second PCI-E x8 slot, and connected it to the 12v sata power rail. 
Upon booting my system up the card "just werks", no driver installation required, my system now has two powered type-c 3.1 sockets on the back and I am fully ready for the oculus quest link when it becomes available. 
I have been testing it and it is powering my quest just fine, file transfer is working flawlessly, as far as I can tell these sockets work perfectly. 

If any other quest users here have a computer which does not natively support USB3.1 (Type-C is not required for link but fuck it, right?) then I'm sure I can dig out the link for you, I think this sort of device is kind of a minefield and there are many out there which likely don't entirely work.