Crappin you Negative came from a Jim Thompson book ( I think pop1280 ) although in the book I think he says Crappin you negatory. Then someone pointed out it's usage in Raising Arizona so we changed it. I like to think that the Coen Bros got it from Jim Thompson as well.
Considering the Coen Bros' almost incessant references to hard-boiled fiction, I'd say you're probably right.
"Raising Arizona" isn't exactly my favorite Coen movie, so I haven't seen it enough to be 100%, but I thought they said "negative" as well (web search shows results both ways)...I had just always assumed the expression was something of a southernism.
Ain't My Lookout came from an issue of Jim by Jim Woodring.
Really? Vol. 2? Y'know, I vaguely think I remember that...maybe.