Thunderbolt to usb 3.0 for win7 install 2011 Macbook Air

I'm looking for a way to install win7 on an external hdd. From what I understand, win7 views the thunderbolt port as pcie, so it thinks it's an internal hdd. Is this true? If so, do they sell thunderbolt to usb 3.0 cables? I don't want a huge docking station nor do I want an external thunderbolt drive. I'd much rather have an adapter so I can replace the hdd when it fails.