"Saved by the bell" and "dead ringer"
"Graveyard shift" and "wake"

I'm also very suspicious of "dead drunk". Acute lead poisoning isn't something you recover from in that way, and anyone can easily tell the difference between being unconscious from booze and being dead. This goes double for back then, given that around half of all children died before adulthood, and adults died pretty easy too. Back then, you'd have had plenty of experience of what a dead body looked like. Anyway, the metaphor is so blindingly obvious, I don't see how it needs any further explanation, any more than "sleep like the dead" would.

And checking the family history of Walter Scott shows no such story.

In other words, Muttley, it looks like you've been taken in by yet another piece of internet fakelore spam. :-/

Graham.