I am asking this because the only person to have commented on the answer in this didn't get a response.
Is the chosen answer in this question
http://answers.unity3d.com/questions/1235/version-control-workflow
possible in the free Unity.
Yes, it's entirely possible, there's nothing about that plan that requires Unity Pro. There's no script you can download, though, it sounds like this guy's team created this system from scratch.