Well, at least a first prototype: http://www.utopiaedit.org 
Very nice 
and funnily enough, something I was thinking about after (ab)using hackpad.
Please note that there are intermittent freezes (spinner for 10-15 seconds when loading data). Guess they are due to Meteor hosting service…
Here is another sample project, to see how it would look like when applied to discussing a political platform: Pirate Party Australia.
Hey, was wondering if this is collaborative in the same sense that google docs is collaborative… e.g. some type of Operational Transform implementation or other CRDT?
UtopiaEdit uses a custom lock mechanism: when a user edits a subsection, no other user can edit it.
Cool, I just started a discussion about this sort of thing over here WYSIWYG Editors and Collaborative Edit Safety, any insights or experiences on that locking mechanism would be more than welcome.
Also very cool project. I missed it when you first posted it. My hobby project in Meteor is a wiki type application so cool to see other approaches.