Released USBNet 0.10.N, which includes, besides updated binaries, the unique MAC address stuff discussed before.
As mentioned previously and in the comments of the config file, I wouldn't recommending enabling this unless you really need it, the way it's implemented isn't really pretty
.
It's hidden behind a config switch, so you will need to update your config file manually if you have customized it. There's now a KUAL button that restores the default config, and the default config is available in usbnet/etc to ease manual merging.