F. Savalas, I am from Alabama. I have done phone support for computer S/W before, and I have at least weekly been asked if I'm from Texas, usually by a Canuck or Northeasterner. Those are the same group that mis-hear me when I introduce myself as Mike, and call me Mark.
I am astonished to hear that Caine's accent rings true to you. Both my wife (Alabaman) and I cringed thru the movie when he spoke. No "in your grill" argument, as I certainly can't tell you what your opinion should be in this matter.
I now also recall Shirley McClain's (sp?) "accent" in Steel Magnolias. Buncha hooey.
Regional accents are making a comeback, I believe. It was popular opinion in earlier decades, when major corporations paid to move employees from one section of the country, and there was much more internal migration, that these accents would sort of blend away. Now, I doubt it.