I have exactly the same problem.
Because we have “over head” pages like about, contact, edit, comment, etc… etc…
And we have pages that are focused on content… Some Subject, Some Sub-Subject, Some Sub-Sub-Subject, etc.. etc.. (Example: Chicken, Chicken Soup, Chicken Soup Recipes)
It would be ideal if we could define a choice of rel=”follow”/rel=”nofollow” for each link in our site. Or groups of links.
Perhaps when creating the individual pages/blog post/articles
I personally want to focus my PR on content pages… not overhead pages. This is better for everyone involved. It is better to help people find relevent content… not links to overhead pages.
It would be awesome of something like this existed in WP.