KB 928839 was released this week, and lets you generate a memory dump (inside a VM) by holding down the CTRL and pressing SCROLL LOCK twice.  It builds on KB 254649 and has details to prevent a crashdump on the host.  (I hadn’t thought about that until it was mentioned?!)

All the details are in KB 928839 How to use the keyboard to generate a memory dump file on a Virtual Server 2005 guest computer and a snippet is below.

  Manual Crash Dump

Interesting enough you have to remove the Virtual Machine Additions, but as you can see it works just fine under Virtual PC 2007.