Note that on the Ubuntu Mobile Wiki, they state under UI Framework that "Several engineers from Nokia are helping with this effort (Thanks!)."

I don't think that Nokia would lend engineers to the Ubuntu Mobile project without getting something in return. I would be surprised if the Hildon Interface demo'd on Ubuntu Mobile doesn't end up on the Nokia n800 at least. Question is, will it come with the next OS/firmware upgrade or will it come out when the first official version of Ubuntu Mobile is released in October? Or will the two releases coincide? At least we don't have to long to wait to find out.