Adding something like this is nearly impossible at the current state of the engine. That level of modability is our goal, but tbh at the current speed of development it won't happen in years.
Some time ago @piotrdz and I have started refactoring of the main CObject class and all code that checks object types with if(type == OBJECT_SOMETHING), but it's far from being able to easily add any new objects to the game at all, not to mention loading them with full specification from files.
Another problem we're working on is designing and implementing animations in new model format and extracting all existing hardcoded animations from code. The new animation format should not actually be any kind of code files, just plain data. So far nobody suggested a good design of that, and that's what we'd really need at this point.
Some time ago @piotrdz and I have started refactoring of the main CObject class and all code that checks object types with if(type == OBJECT_SOMETHING), but it's far from being able to easily add any new objects to the game at all, not to mention loading them with full specification from files.
Another problem we're working on is designing and implementing animations in new model format and extracting all existing hardcoded animations from code. The new animation format should not actually be any kind of code files, just plain data. So far nobody suggested a good design of that, and that's what we'd really need at this point.