There's a OneNote Metro app. And when you have Word open for example, you can select Touch mode which spaces out the icons more. As far as Metro versions for Word, Excel, and Powerpoint I don't believe MS have commented on it.
Yeah it works fine. but its not really touch optimized is it? I guess it's designed to work with the touch cover in trackpad mode.
Look at OneNote Mx app vs OneNote2013 - the former I would call more of a tablet app and the latter a desktop app running on a tablet - if that makes sense.
I understand what you're saying. But, if you use Office without a touch/type keyboard, the on screen keyboard takes up like 65% of the screen, with only a small area to see what you're typing. Ideally, Office needs to be used with a keyboard, so I don't see how metro versions of those apps would help anything other than making it look "clean".
Like I said before, there is a touch mode in Office that space the icons out so they are easier to touch with fingers, so in a way it has been optimized for touch, but given the nature of the program you'll want a keyboard to get the best experience.