I'd look at implementing the good ole' crab trap technique. In short - operate with 2 structurally identical DB's. One is the one the users can enter into, edit, etc....the other is the "approved stuff". On a specified interval, run a compare between the 2, and allow the higher-ups to approve/deny each of the changes.

Not all that different from GSquared's idea, really. It's just sometimes a little easier to do it that way than to try to shoehorn it all into one single set of objects.....