I'd like to have a tool that backed up Windows documents to the Mac documents folders, where they are backed up onto .MAC or elsewhere. One trouble with Parallels, is that an incremental Macintosh backup can't afford to back-up Parallels without using up too much space. Every once in a while, I have to back up the complete Parallels files, but *not* every day!
You can use reverse file sharing to allow Mac access to your Windows disk inside Parallels VM. And you can tune your Mac backup utility to take files from reverse shared folders.