I've always loved
Letitia. It's so classy and sophisticated. Some people are out off by the "tit" in the middle, but I don't mind. I guess if it's really a problem you could always spell it
Leticia. I like
Letty as a nn even though it reminds me of "lettuce". Tish is cute, too; it sounds like the kind of nn a wealthy family would give a child.
Laetitia is such an elegant spelling. Too bad it would probably confuse too many people.