I too am very interested in if they are currently supporting Windows and/or if/when they plan to. I was hoping this blog post would have at least mentioned it in passing.
I wonder how hard it would be to use the NTFS pseudo-files that OneDrive used in Windows 8.1 (and abandoned in Windows 10 for being "too confusing to the average user")?
There's always the ability to use a SAMBA server variant and be a network share. Still a lot of dumb Windows apps that fail on network shares, but most of those are long in the tooth and should be retired anyway (and the tried and true Map Network Drive is still a power user workaround).
It looks like one application I use (JungleDisk) is somehow faking a removable drive (such as USB). I'm curious how they've built that.