The operating systems that are getting support are mostly or at least partly open-source, so good luck with that.

That's probably not as big of a detriment as the high level functionality Windows expects to be in the filesystem layer that unix doesn't (or puts in VFS). From what I read, this is why Microsoft themselves have a hard time replacing NTFS.

There's having ZFS running as a native Windows file system...

...and then there's running ZFS on my Windows systems, which I must use a special API to access.

The second one isn't ideal, but it would be awesome to have.

There is http://code.google.com/p/zfs-win/ ,but it is not really useful.

You might be surprised at what WinServer 2012 already supports in that area: http://www.microsoft.com/en-us/server-cloud/windows-server/s...

You might be surprised that if you pay more money, Microsoft has more to sell you.

No, I'm not. I like FOSS, and ZFS seems excellent - I wish it made it to Windows. Like, Windows 7, for consumers and businesses...