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.
It seems like it's using blocks that are half a character tall, and I imagine using the combination of foreground and background colors to get two colors into each character space.
Therefore your horizontal resolution will be equal to the length of each line in characters. Your vertical resolution will be equal to two times the number of lines on the screen. So maybe it's doable with high resolution and tiny font. I don't know what the limits for those are.