PHP / MySQL Content Collaboration Suite?

Hi All, Some friends of mine and I are embarking on a creative writing project and I've been looking around to see if there are any reasonable web-based creative collaboration suites / apps available that might suit our needs. In lieu of any other place to start, I've been looking at messageboard forum solutions (eg Invision Powerboard, phpbb etc), blogging solutions (MovableType, WordPress etc) and CMS solutions (PHP-Nuke, Drupal, Xoops etc). It seems to me that the best solution would combine many features from all 3 of these types of suites, and I'm curious to know if anyone has already attempted to tackle this as a project in and of itself? If so, I'd dearly love pointers to any suites that have aimed themselves at creative content collaboration, and if not, I'm curious to know if there'd be any developer interest in attacking this from an open-source perspective? Much warmth, Murray