It would be great if you could add the ability to add a "Project Role" to client contacts assigned to a project, similar to how you can assign employee roles. Then add the ability to reference these roles in a report or invoice as a variable.
I'm think of this in the context of adding a contact for a multi-project report or summary. We send reports for multiple projects to one of our larger clients, and it would be good to be able to include a Project Lead to each respective project that listed in each data row of the report or invoice.