I want version control to my Word documents

I noticed that I've got probably quite addicted to source/version control in Visual Studio Team System (VSTS): I'd love to see a similar feature in Word, and directly from the operating system!

Of course, I could today use Windows Vista's shadow copies ("Previous Versions"), or Word's tracking of changes, or keep VSTS running and copy my projects there, but none of these solutions seem clean enough for me. Vista's Previous Versions comes quite close, but the problem is that it doesn't keep that many old versions, and isn't even guaranteening any previous versions. Maybe I need to hack a simple VSTS client that integrates with Word 2007. :-)