[Agrajag]

I suspect its possible to code in multiple turn orders without throwing away all existing code, and probably without much impact on turn resolution time, though it would take some time to code, and UI work :O
Just make it so you can queue orders onscreen, which on the .2h file are represented as more order under a different sector, marked "should be done in X turns", and at the end of the turn resolution process, just make the block for the next turn's orders into the next turn's .2h file (and the blocks for "in x turns" into "in x-1 turns"), then just like you load a game now and get a choice wether to continue the save or erase all orders, you'll have the .2h file for this turn's orders.
My idea obviously has several drawbacks:
1) It assumes that invalid orders are disregarded, rather then cause an error.
2) Would make MP more cumbersome, since it would require lugging around both .trn and .2h files for each turn.
3) Would require quite some coding work, especially dreaded UI work.