I'm using a workaround for the smoke issues. aka setting all smoke to have a 100% chance to dissipate and made the smoke chance of all weapons to none. I did however resolved this crash by having one soldier Scout around the map once more before I killed the last of the xeno scum. So it looks like it wasn't the rubble. Still don't know what exactly caused the crash.
https://docs.google.com/file/d/0ByqwN9aAAGY0a1NmSE8xVzJ3bXc/edit?usp=sharing
This save I believe is the one that contains the crash, as soon as you kill the last serillian the mission ends and after the soldier dev screen it crashes to desktop.
Whenever I finish a terror mission against the serbians in where I cause the roof of a building to cave in the game immediately crashes when I finish the mission and press go after the soldier development screen.