Already there, in bits
There are two main avenues already...
1. VNC : why ask what's on screen, if you can ask politely to see their screen, open task manager, etc.
2. Reporting tools.
a) Microsofts has quite a few WMI based scripts, perfect for gathering information on demand - remotely even.
b) While a lot more expensive, Lavalys Everest has a remote audit, which can grab DLL versions, processes, software versions, event logs, PCI info, and even grab screen shots of applications or all of windows current desktop