Sorry for double posting, but this post has hung in the Netflix forum for a while without a reply, so I thought maybe the readers/moderators of this forum may be better able to answer the question.
I'm a developer for linuxMCE (http://www.linuxmce.com), an open-source Linux-based home automation system. We use MAC addresses to detect when new devices are attached to the network and configure to use them. Right now, we have a range of MAC addresses for Roku that we use to detect when a soundbridge is plugged into the network. We simply use the first three bytes of the MAC address to set the bounds of the range.
It looks like the Netflix player's MAC addresses (at least the one I bought) is in the same range. Does Roku have a range of MAC address dedicated to each, or do they share a single range?