Virtual Virtualization lab

I'm doing some preparation for some cross training I'm doing on Friday on VMWare Virtual Infrastructure 3. I've used some old servers to create a lab environment consisting of a virtual SAN (using SANMelody) on one to act as an iSCSI target, another server as a VirtualCenter server and two old Dell PE2650s as VMWare ESX 3.5 servers. This works fine for VMotion, DRS, HA and all the other good stuff that VMWare supports but still takes 4 physical boxes, two of which need to be multiprocessor or multicore and have a fair amount of RAM. In a pinch you could get this down to 3 servers if you combined the VC server and the SANMelody server onto one box.

Then I got to thinking, I know people have installed ESX Server as a VM under VMWare Server or GSX Server so would it be possible to create all four machines as VMs on one physical box? This would let me give the two people I am training their own server (the PE2650s) and they could run through the entire setup on their own.

I'm going to have a go myself today and see what happens.