Expanded project management ala phpCollab

I've used phpCollab (http://www.php-collab.com) for a while on web and multimedia development projects. It works great for both the development team and clients who need secure/private access and a simplified view of project management.

It would be great if a similar module could be developed for Drupal or the existing project module were to be expanded to include some of these useful features:

• multi-level task hierarchies or taxonomies (i.e. like phpCollab's phases > tasks > sub-tasks)
• task start date/time, end date/time, percent complete, estimated and actual durations
• to-do and milestone dates calendar view
• interactive gantt chart creation (using jpgraph or pure XHTML + CSS)
• separate client and developer views
• integration with (or linking to) other content types such as contact, calendar, gallery, comment, forum, book, file, e-commerce etc)

Drupal and the existing project module can easily handle all the admin functions and other "trouble ticket" type features, but adding the above features would increase its utility beyond tech support and software development into general purpose project management.

What do you think?

Brian.