Would it be feasible to give a certain user different permissions levels for different projects? So they were a manager on Project 1 and could edit it, but were only an artist/viewer on Project 2 and couldn't make changes to it?
The particular use case we have in mind is stopping people who are managers of one show accidentally making changes/deleting stuff from other shows thinking it was their own ("I don't recognise all these shot codes! Better delete them!" - sadly true to life)