Hello,
Right now there is a situation when you want to make a copy of some assembly (even with some sub assemblies) you make it by vault or design assistant or save as an then replace components. Ok but all this examples take a time. My idea is to add copying tool directly to Inventor app. There are some addins ex CopyDesignTool in autodesk addins and i use it. But why not add something like that directly to Inventor. This tool should have option to change filenames of components, checking all dependencies between files, also copy drawings.