First of all, if these hosts are using dhcp, then they aren't worth monitoring. The customer will surely tell you when his disk is full, and if that does happen, will it shutdown production? I doubt it.
But servers will have static ip's, and servers are what you should monitor since they can shutdown production.
Also, you want to monitor all of the switches, routers, ports on the switches, etc. But a customer's pc that has dhcp? Sorry, I have no idea how to solve that problem.