When you or a contact has a cam on, the "last message recieved at blah blah" messsage is replaced by Connection Established. However If they start typing, it does go away to replace with the "contact is typing a message" message.
You've guessed it already. How about a feature / plug in allowing u too see when the last message was recieved whilst a cam / cam's is /are on?
I'd use it!