Windows 7 network fallback from LAN to WiFi
Nope. Linux, Mac OSX, FreeBSD, etc can all do this, but Windows does not have any built-in link aggregation capability. There may be 3rd party software that can make it work, but not just Windows.
It's not free but it's got a 30 days trial and costs about 8$ if you decide to buy it: Wireless AutoSwitch XPV
I don't know of any way to do it natively in Windows.