Smurphy: here's an idea I have for a trigger solution for the repair problem. Give each player a nominal number of minerals (eg 5 or 10) and gas (only once the computer has gas). Have a trigger that "charges" the cpu money every time players' cash gets deducted for any reason (eg leaving or repairing). Also have this trigger keep track of debt and attempt to zero all players' minerals when the CPU has 0 minerals or gas. With this example upon leaving you'd only end up transferring 5-10 minerals to the rest of the team...which, while bad, isn't a disaster...and the trigger might just go ahead and subtract them when it notices the players no longer own those resources.
I can try to add those triggers for you if you can send me your map file at some point.