I'd like to be able to set some sort of away message on my lock screen.

Basically somtehing like "Gone for lunch, back at 12", "Coffee run, back in 10 minutes.", "In a meeting".
Some script to...

Actually, GBInfo has an option to update the background image on the logon screen. Not sure if this works properly on Win10 though. (On my work machine I apparently do not have access to the registry...