If you have that many computers to manage, why do you not have a SAS and have all of your important data in a centralized location?
They probably are. They're looking to monitor 300 individual workstations.
The way you're talking, you're wanting some sort of stateless machine sitting there that opens a VM when started.... Not exactly inexpensive if you don't want use the existing machines that started the question to begin with....
I've seen some home brewed SNMP tools that can do this....not that it offered anything useful though...by the time anything was recorded the drive was already tango umbrella.