I am a native speaker of AmE aged 66, and the only person I have ever heard utter the phrase was Elvis. (To be fair I should add that I am a Canadian, not a southerner like Elvis.) I've always thought it was one of those 19th-early-20th- century phrases coined by pious people as a substitute for words they considered objectionable. It was a substitute for I'll be damned, goddamit or something like that.
- For Teachers