I don't see why this wouldn't work, it doesn't matter if you use fiber, LAN or radio, its the (R)STP protocol that finds loops in the network and disables redundant paths.
If you set up a wireless link that will pass through all L2 traffic and disable any STP on them, then all STP packets will go via the links, they will act as cables.
So the switches will "think" that they are connected directly and will suspend one of the 4 ports that take part in the communication and if one of the connections break, the other one will take over.