Mapping a wireless network dynamically.

[kitepilot at kitepilot.com]

So I want to map my network "on the fly".
This is what I already know:
Radios are Wiligear (embedded Linux)
I have a script that logs in into every radio and downloads its 
configuration file, MAC and IP address. 

 From the configuration file I can tell APs from bridges. 

I can login in every AP and grab the list of MAC addresses associated to 
that AP.
I can find the corresponding IP address of a MAC with a lookup into the ARP 
table of the firewall.
Now I can login to those bridges too.
So far so good... 

Now the challenge:
When I login to the bridge, I need to know the MAC address of the device 
attached to the eth0 interface.
How do I find the MAC address of the device in the other side of the wire?
Thanks!
ET 

PS: Message kept succinct for practicality, please feel free to ask 
questions like:
"what else do we have available?"
Well, SNMP, but can it be used for this?
It's Linux, give me your wish list...   :)