You can adjust Luc's code a bit so that it exports the original info along with the MAC address.
It would be something like:
## save the imported info $colVMInfoFromCSV = Import-Csv $importfile
## add a NoteProperty to the info (later to be a "column" at Export-Csv time) $colVMInfoFromCSV | Add-Member -MemberType NoteProperty macaddress -value $null $colVMInfoFromCSV | %{ $vname = $($_.Hostname) New-VM -name $vname -VMhost $vmhost -ResourcePool $pool -DiskMB $disksize -MemoryMB $memsize -NumCpu $cpu -DiskStorageFormat thin -Datastore $datastore -GuestID $os -NetworkName $nic0 -Location $location $macnic1 = Get-NetworkAdapter -vm $vname | where {$_.type -match "e1000"} | select-object MacAddress
## put the MAC address in this "row" of the collection of info (this object in the array of objects) $_.macaddress = $macnic1 New-NetworkAdapter -VM $vname -NetworkName $nic1 -StartConnected -Type vmxnet3 New-NetworkAdapter -VM $vname -NetworkName $nic2 -StartConnected -Type vmxnet3 }