I started a thread about one such person recently but didn’t get any replies. Here was part of my OP. Everything I can find suggests that he is a real person despite sounding like he is from Transylvania. He has the most bizarre accent and speaking style that I have ever heard. His stories linked below are worth a listen.
The Kennedy family may also count. They have (or had) their own very strong accent. Despite living in the Boston area for 20 years, I have only met one other person that talks even remotely like they do and she may be related to them as well for all I know.