Funciona com as seguintes regras, que certamente podem ser melhoradas:
KERNEL=="sd?" SUBSYSTEM=="block" SUBSYSTEMS=="usb" ATTRS{devpath}=="1.2" SYMLINK+="usb0"
KERNEL=="sd?" SUBSYSTEM=="block" SUBSYSTEMS=="usb" ATTRS{devpath}=="1.3" SYMLINK+="usb1"
KERNEL=="sd?" SUBSYSTEM=="block" SUBSYSTEMS=="usb" ATTRS{devpath}=="1.4" SYMLINK+="usb2"
KERNEL=="sd?" SUBSYSTEM=="block" SUBSYSTEMS=="usb" ATTRS{devpath}=="1.5" SYMLINK+="usb3"