What software product can I use to scan a wireless or wired network device in order to get it's unknown IP address. Basically I'm looking for a product that can pull not only the MAC but find/request (or beat) the applicable IP from an unknown IP addressed device.

Follow me on this:

a) There is no access to the web to download the manufacturers manual prior to or during the work. (and probably wouldn't be if the device is a gazillion years old)
b) There is no one that I can call to have them look on the web while I'm working.
c) There is no access to the web based configuration since I don't have the IP.
d) The client has no product manual available.
e) SNMP scans are powerless.
f) Factory resetting the device isn't an option since I still don't know the default IP and a normal scan of standard configurations don't work. (depends on the item in question, of course).
g) The device is not responding to manual IP subnet scans of the usual IP configurations normally seen in a network.
h) Banging the object against a desk only works partially.. :-)
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Normally I use a variety of methods and tools to get what I'm needing, but in some occasions they just leave me hanging.

Oh... and I'm still looking for that magical software that allows me to be on, say 192.168.2.x and scan for IP's on any OTHER unknown subnet without forcing me to change my IP configuration.
(no VPN's are included in this scenario, as they DO allow that kind of behaviour)

Thanks.