There's one possibility that occurs to me: the "FlashPath" is a floppy disk shaped adapter for SmartMedia flash cards, which goes into a floppy drive. Sony made them for their floppy-based Mavica digital cameras. I have no idea if they require drivers on a Mac - ISTR they needed them on PCs. If they do require drivers, then they would not be bootable and would need to be used with a second internal or external floppy drive - if Mac drivers even exist. And they will be slow. They also may not be compatible with 400k/800k drives.
Still, worth looking into perhaps?
Apart from that, seems to me someone needs to get busy with a microcontroller and the serial port, or a logic analyzer and reverse engineer the floppy drive connection protocol.