Well finally got my Maximus AVR USB device. Tried the hex listed here and none worked. Even the original AerialX files didn't. Not saying that they don't work with the devices available, but it doesn't seem to work with the Maximus AVR USB, which is weird as it's based off the AT90USB162.
Plugged the device in, installed all the usb drivers for win7, found the device, erased, check, flashed, check. Ok with Flip. Then plugged in console, no leds, nothing. Tried the AT90USB hex and that seemed to work flashing wise, but the other ones (blackcat, teeny) stated error flashing. So found MAX_AVRUSB_psgroove.hex and used that [that seems to be based on the original psgroove hex]
Straight away after flashing, the LED lit red, and Windows detected the USB Hub device. Plugged into the console and booted into debug. Was able to install the FTP as The Last Guy demo, which was cool. So even though the hex here works with other devices, it doesn't seem to work with the Maximus device. Not sure why, if you want me to upload the hex for that device for sussing out, let me know.