Ah, I'm sorry to hear this feature hasn't gotten traction. I'm perpetually hoping to see it in an update one day. Since it sounds like that's unlikely to happen anytime soon, has there been any consideration of other ways to achieve similar results?
I tend to start lots of simple little projects, and many of them have similar elements. For example, I often want a bitmap-based progress bar. I've built a system for this in event sheets using a combination of sprites and 9-slice objects. The logic for it is pretty trivial, but it's still a pain to recreate it in every project. I don't want to (nor do I have the ability to, really) write a dedicated plugin for it - I want to leverage all the powerful classes already in the engine.
It's already possible to manually copy pieces of my system from one project to another, but this is pretty tedious and involves a fair amount of work for each feature I want to rebuild - I still need to create all the objects/families, variables, etc. before copying and pasting the event sheet logic. In some of my more complicated systems this process can take a long time and is pretty error-prone. So, it would be great if there were some easy way to bundle a bunch of related families, objects and event sheets into a package that can be imported into new projects. Any hope for something like that?