Interesting. I've been using blender executed from command line for my work for about a year now. It's a great and powerful tool that can be used to automatize some 3D processess (e.g. conversion, optimization, rendering, textures-baking). As far as I know you can't pass any arguments (e.g. path to some external file to be imported and processed) to the script which is executed after starting blender, but you can write all the important data (file paths, etc) to some file (saved in fixed-location relative to blender), which is read by the script.