With this line one would get every VM with the old hardware version.
Get-View -ViewType VirtualMachine | Where { $_.Runtime.PowerState -eq "poweredOn" } | Select Name, @{N="VMVersion"; E={$_.Config.Version}} | Where {$_.VMVersion -eq "vmx-04″} | Select Name
It should be an optional switch, because in a VI3 environment it would
MCP, VCP