@Will Anderson - You are right about it being 'H' related. If you want to read more about the details I did a post about it on another blog: http://www.habari-fun.co.uk/my-theme-project

I haven't used private pages, but I have added an extra field to specify what kind of page it is. In theory they could all be accessed directly with the right url.

Let me know if you want any particular specific details and I'll happily disclose.