Internal PowerShell DSL for VM template descriptions. A Hyper-V, or Azure, provider would actually instantiate from metadata (see bottom).

box.ps1

set-psdebug -strict

# bleh
# 
$global:boxes = @{}


<#
Here we are defining an internal PowerShell DSL for creating 'boxes'.

#>
function box()
{

  param([string]$name, [scriptblock]$block)

  
  BEGIN
  {

    $script:basebox = $null
    $script:cpu = 1
    $script:memory = "1GB"
    $script:windowsRoles = $null

  }

  PROCESS
  {

    write-host "PROCESS"
    
    function basebox($basebox)
    {
      $script:basebox = $basebox
    }

    function cpu($cpu)
    {
      $script:cpu = $cpu
    }

    function memory([string]$memory)
    {
      $script:memory = $memory
    }

    function windowsRoles($windowsRoles)
    {
      $script:windowsRoles = $windowsRoles
    }

  }

  END
  {

    write-host "END"

    # this will actually execute all the variable assignment
    # in the brackets (scriptblock) below.
    #
    # box "mybox" {
    #  cpu 4
    #  memory 2GB
    #}
    
    invoke-command $block
    
    $box = new-object object

    <#
      are we defining a new box based on an existing box?
    #>
    if ( $script:basebox -ne $null )
    {
      $box = $global:boxes[$script:basebox]
    }
    else 
    {
      add-member -inputobject $box -memberType NoteProperty -force -name "name" -value $name
      add-member -inputobject $box -memberType NoteProperty -force -name "cpu" -value $script:cpu 
      add-member -inputobject $box -memberType NoteProperty -force -name "memory" -value $script:memory 
      add-member -inputobject $box -memberType NoteProperty -force -name "windowsRoles" -value $script:windowsRoles 

    }
    
   

    write-debug "adding box $($box.name)"
    $global:boxes[$box.name] = $box

    $box
  }

  
}

# create a box from an existing template
#
function new-box($name, $from)
{
  
  write-debug "new-box ($name, $from)"

  box $name {
    basebox $from
  }

}


<#
this would actually be defined in something like

wserver2012small.box
wserver2012standard.box

and kept in source control.

Very simple definitions here - there would probably be many more attributes to configure.

The 'box' PowerShell API would allow us to do something like:
#>

box "Windows Server 2012 Small" {
  cpu 2
  memory 1GB
  windowsRoles "ServerCore", "AppServer", "WebServer"

} | out-null

box "Windows Server 2012 Standard" {
  cpu 4
  memory 4GB
  windowsRoles "ServerCore", "AppServer", "WebServer"
} | out-null


<#
load the box API into our current session
we can also update our PSProfile to include this on each load
#>
. .\box

# now create a list of servers based upon a template
#
$servers = "Web01", "Web02", "Web03"
$servers | % { new-box $_ -from "Windows Server 2012 Standard" }

# Maybe.. :)
#