Obtaining a comprehensive, automated backup of your domain Group Policy Objects has always been a challenge.
First, we had the GPMC WSFs (Windows Script Files) and then the glory of PowerShell and the Backup-GPO cmdlet. However, like a single chunk of chocolate, they were never quite enough... so I wrote a sample script to obtain a comprehensive group policy backup. What's more, there's a companion script for performing an import of the backup to a test environment.
A full write-up for each script can be found on the 'Hey, Scripting Guy! Blog':
The scripts can be found on the TechNet Script Repository: