I recently came across http://www.edu20.org . It is branded as an LMS (and positions itself against Moodle) but has the potential to become more.
I have been working on a model for a school intranet, that connects governance, planning, project management, and LMS functions at http://empowered-teacher.com/about/drupal-environment - but it's just ideas at this point, ripe for custom development if I found the right school. Jim Heynderickx's diagram: http://www.k12converge.com/wp-content/uploads/2010/02/Visio-Comprehensiv... is a good starter to visualize what kinds of things a school Intranet needs to do.
Question (once this group is approved): who among you has adopted Drupal as an Intranet backbone for your schools (including integration with other solutions like Moodle) and how is that working out? How would you position Drupal's potential against other solutions that are custom-made for schools (like SchoolNotes)?
Acquia is developing an enterprise Intranet solution called Drupal Commons (http://acquia.com/products-services/drupal-commons) - I wonder if this might be a starting-point for a K-12 solution....
-Bram