I't may be possible to write a script to grab the system information and make it write it to a database or something, ie, record the ip address and any relevant information. I have done this for our unix machines but not for windows but i bet with a scripting language (asp, php) you might be able to grab the system info although this may take longer depending on how many machines you have.
All our windows servers are rackmounted so connecting monitors and keyboards to each of them would be a nightmare. We sometimes use a utility called sisoft sandra which tells you lots of useful info about the system, ie cpu speed, motherboard make and model, memory type (pc100, ddr etc) and even cpu temperatures and fan speeds (useful for rackmounted stuff when you're away from it).
do a search for sisoft on google and you should find it quickly enough.
you could load the setup file onto a network server and run it on each machine remotely with something like pc anywhere.
Hope this helps
Rob