There have been a nice gentoo SoC project, which is a ajax xml editor for gentoo's specific xml doc syntax.
The result is amazing (still has some bugs however..). Read all in his blog entry: http://summerofcode.wordpress.com/2006/09/29/beacon-02/
on-line demo: http://guidexml.soc.gentoo.org/guidexml/editor/
Next year we can propose a project for SoC to adapt this to livedocs :)
Looks promising! Imagine, while viewing the manual you spot a place that should be modified... so you click the edit button in your browser, edit the text, submit, then reload the page seeing the modification show up immediately. Is this simply a fantasy or will it be reality? Only time will tell! :-)
Regards,
Philip