How about a web interface?
 

Just a thought, I don't know if this has been mentioned before. But what about something like what Taskpaper has in the works, a web interface that would sync with the desktop app. Obviously that app doesn't have the complexity of OO, but since there's talk of an iPhone app that would be a simplified version, maybe that could work.

I think us Windoze users would like it.

Of course, OO 4 has been in the works for years, so I guess another project is just kooky talk anyway.