Looking for project log feature for posts

I am looking for a plugin or other code resource for automatically adding a project log to a post upon post creation.

We’re developing a site for a client whose posts are descriptions of collaborative projects, and they want to allow team members (registered users) to enter progress or action on these projects. Ideally a project (post) is created and there is a project log underneath the title/content. The functionality of the log can be very spartan — individual log entries can just consist of a single field tagged with with the team member’s username.

Any help appreciated. Thanks!