not sure if you guys have also tried hooking up an external USB connected DVD drive. It works. That is, you can also play regular DVD media via the external USB DVD drive connected to the EGREAT. :-)
I did the same via XBOX360's HD-DVD add-on kit, it can see the HD media, but can't play it. On the other hand, using the same external USB HD-DVD drive, it can read regular (legacy) DVD titles without a hitch.
Hope this helps.
-JackRyan