If M$ pushes this too hard, it will make a big mess. Ideally, we'd end up with any of the open-source FSes (or a new lightweight one) except that you need a Windows driver for said FS. I know some people who've been involved in porting AFS to windows and at the time, it sounded like the license terms on the Windows FS SDK (which costs $10K or something) were essentially such that you couldn't redistribute code that you wrote against the API.

RE: FAT File System Technology and Patent License