I think this would be a huge time-saver for games with high ship caps:

 

When a unit in a fleet is destroyed, replace it with a "dead ship" that has a crossed-out icon in the selection bar and does not exist on the map. Have a fleet action called "Replenish fleet" on the orders bar. when the button is clicked, find the nearest idle shipyard and get a list of all idle shipyards that many hops away. The action will issue build orders for all dead ships, distributed among that list of shipyards.

1. Ships in a factory queue will know the IDs of the dead ships they are replacing.
    1a. When a ship is built, destroy any associated dead ship and add the new ship to that fleet.

2. Dead ships will know the ID of the shipyard that is replacing them.
    2a. When a ship is removed from a queue (manually, or if shipyard is destoryed), remove the shipyard ID from the associated dead ship.
    2b. The Replenish fleet action will only replace dead ships with no shipyard ID.

3. If a fleet is re-formed and there are dead ships not assigned to a fleet, destroy these dead ships.

4. Titans that get destroyed do not get replaced with a dead ship.

 

This also would be great for sustained assaults, with this feature you could keep the camera focused on the battle, instead of having to move away once to build ships and again to bring them to the front.


EDIT: Got posted before I was done.