There are several different ways to add MultiPlayer to a TBS,,so if you find my idea lacking in some aspect,,or have a better and/or way to get the job done,,add it here!
As example,,I'll use a four player game:
Player 1 (human:host)
Player 2 (human)
Player 3 (computer)
Player 4 (human)
What I'm suggesting is basicly a hotseat variant,,where the 'seat' is moved around the game participants computers.
The reason for this is that simultanious moves would change the game completely,,thus requireing total recoding.
Since the AI can compute it's turn in the background while the player takes it's turn,,there is no reason human players shouldn't be able to do the same.
That means while player 1 plays turn one,,the others can set production,,taxrate etc.
When player 1 is done and hits the Turn button,,player 2's new settings take effect so he immediatly can start moving the ships and then finish the turn unless the actions of player 1 neccesitates some changes.
The information of things done would be transmitted upon clicking the Turn button,,either by true PBeM or by the info pack being sent to the hosting comp and then submitted to the other participants.
The latter would allow for LAN-games without the need for an email server.
It also would allow StarDock to put up a central server for hosting the games without the demands of bandwidth,,ping and storage that for instance Blizzard's games require.