I might misunderstand what you mean here, so for what it's worth: I have land transport units in my mod, and I've managed to trick AI to use them to transport other land units. It doesn't use them very frequently, but land transports with loaded units can be seen occasionaly in open terrain (see attached image). When attacking an enemy land transport loaded with units, you will have to fight each of the loaded units before destroying the land transport (unlike sea transport where the vessel is attacked first and the loaded units drown when it is sunk).
Aside from the discovery, your mod looks very interesting. Is there any chance you might release it sometime?
