Worth every penny, I am on the mailing list so maybe talk to you soon!

So, I was messing around with this more today. I ran across the exact same problem twice in two days, so I figured there must be a reason. I notice that when I image my machines, they would all initially show up with no problem. I image them over Ethernet, connected through a switch to my server. Then, after they are imaged, I zap the PRAM, let them boot, and go into my admin account on each machine to name them.

I noticed that once I'm logged in to each machine, they are connected to my wireless network by default. This apparently is what is causing the problem. They are still connected to my server through Ethernet, but they connect to my AirPort wirelessly, and the Network System Preferences is set to give AP the highest priority.

I switched the priority to Ethernet over AP, and the problem went away, at least on my server side, and allowed me to correctly pull reports off all the machines.

Now, if I try to connect to those machines with my MacBook, also running ARD, on the wireless connection, they all show up with no valid MAC Address. So, what I can figure, is that the MAC Address must be spit out using Bonjour, and (I can't confirm this) Bonjour must only broadcast MAC Addresses to the primary network interface. So if a machine is connected to a network in two different, or two different networks, only the primary network connection will display the MAC Address.

Does this sound about right?

Bonjour by default will not broadcast via WAN, only on the same LAN. Not sure about the rest of what you are seeing. You may want to keep the airport card disabled until you are done with post config to test this out?

Both networks are what I would consider to be on my LAN, just different access points. But yeah, for my next image, I'm going to set the ethernet to be my default setting to avoid this. At least that will be my temporary fix, although it's just a workaround for this problem, not a solution :(