I don't know what could be put in place but I would find it extremely useful if my computer could play a sound or give me a notification when lightroom sends over the export. It would help with effency. I am often rendering 10 timelapses back to back to back when shooting for a client.
could be a simple as a kitchen timer noise at the 100% notification

I will see what I can do...

Please Please Please this would be killer and would allow me to multitask when I am editing.