There's a new paper on our website which discusses how the events team use Windows Server System integrated components including ISA Server and MOM to deliver the infrastructure required to provide services to thousands of attendees at the various shows including TechEd. The paper itself is fairly high level and lacks the "nitty gritty" detail that you'd find at a "how we built TechEd" chalk 'n' talk session. If you are able to go to TechEd Europe or have access to the recorded media then I highly recommend viewing that session.
The paper's good to show you the build methodology and components that comprise the solution. You can access the paper here