but do you think it is also a dream to have a script that convert the Galciv 2 ship model file into a Sins compatible format?
It'd be a lot of work. GC2 ships are a custom format describing a combination of DirectX format models. You'd have to merge them all into one model, then get them into XSI format from there so you can add emitters for Sins. Besides that, I dont' believe either game supports multiple textures per model, so you'd have to merge them all and redo the UV maps as well. At that point you might as well just rebuild it from scratch, since I don't think taking actual graphic assets from GC2 and putting them in a mod for another game (even one of ours) is going to be the most legally sound plan around.