RE: Campaigns

>To maintain balance, there should be some cost to "working to the
limit".
>Perhaps a shipyard could increase it's rate by burning up capacity
(i.e. a
>shipyard of 10 units could operate at 30 units for one month by
sacrificing
>itself)

This could be easily balanced by saying that an increase in 
productivity now MUST be balanced by a corresponding decrease in 
productivity at a later date. By putting a time limit on the 
productivity increase, you can then simulate the exhaustion of 
economies on prolonged war footing.