Any way to add an "It's now safe to turn off your computer" message at the end of shutdown?

I want to do this for my raspberry pis since they don't have an ACPI system in place. I think it would look really nice combined with XFCE and the chicago95 theme. So I would prefer it if it were showing it like the windows 95 shutdown screen, maybe using an image file? There's a lot of information on the shutdown process on linux but not much on the topic of altering it.