Steve:
There is a program can do what you want --  Windows Media Load Simulator

Organizations are building high-capacity servers and server clusters to
serve the increasing demand for streaming media. Microsoft Windows Media
Load Simulator version 4.0 is a useful tool for determining server capacity
and system stability during the planning and development phase of your
Windows Media server system. You can also use it to monitor the
availability and health of a Windows Media server after your system is put
into production.

Windows Media Load Simulator creates a real-world load on a server by
simulating Microsoft Windows Media Player connections; the load-test
results on the server can be viewed in a log. Windows Media Load Simulator
is designed to run on one or more client computers to simulate a large
number of client requests. If you balance the load on your Windows Media
servers for greater scalability and availability, then Windows Media Load
Simulator should be run against each individual server.

Windows Media Load Simulator can also monitor a Windows Media server in
active service, and it can be configured to automatically alert an
administrator when server performance begins to degrade or if the server
stops responding.

Visit the web site
http://www.microsoft.com/technet/prodtechnol/netshow/downloads/loadsim.mspx
and download loadsim.exe from there.

Hope this helps, thank you for using Windows Media Services

David Chen
Digital Media Division
This posting is provided "AS IS" with no warranties, and confers no rights

You may want to try the Windows Media Load Simulator.

This tool simulates a real-world load on a server. The load-test
results on the server can be viewed in a log. Windows Media Load
Simulator is designed to run on one or more client computers to
simulate a large number of client requests.

http://www.microsoft.com/downloads/details.aspx?FamilyID=0304afa3-e414-4dec-82a4
-2d58ac75c833&DisplayLang=en

I read through the Windows Media Load Simulator documentation but this
simulator seems to force all the simulated clients to stream the same
file, so there's virtually no load on the server's storage system or
on the ability of the server to manage requests that go all over the
platters. In fact, the server could just cache this one file and
operate from memory, clearly NOT a real-world VOD environment.  Did I
miss something in the documentation or is this truly a limitation of
the simulator? If this is how it works, does anyone know of a
simulator that does allow each simulated client to access it's own
media file?

Thanks,
Steve