It's cool isn't it. After I did my fast track course on 3.5 I knocked up a training envirnment is WS 6.5. 2 ESX hosts, Openfiler iSCSI SAN for shared storage and VC running in WS VM's. I was able to build a VM within the VM ESX server, install 2k3 on it then vmotion it between betwen the 2 hosts. Ran all this on my Dell Precsision M6300 with 4 GB RAM. It was slow but I could work through all the courses labs quite easily on this training rig.
Paul