This is a great example - I've just been able to adapt it for a project management app, allowing a SQLFORM.grid of projects to link to a project details page that also includes a view of project members and project outputs. 

I've got a question though: I'd like to create a similar setup to create new projects, where a user can create a project and add a set of (existing) users. The main difference is that in this slice, the user already exists so that the manage_user controller gets passed the user_id.  Is there a way to adapt manage_user to get a new user_id to associate with the record being created?