Dolly Copp is well known in my neck of the woods for the campground that surrounds her homestead and bears her name. Irene P. Lambert learned by looking at her handwriting that Dolly was "strong-willed" but "self-conscious, afraid strangers would laugh at her."
Lambert claims to have considerable success with genealogical handwriting analysis.
In 1998, she was tested by the National Genealogical Society Quarterly, which presented her with handwriting samples from James Ball, a colorful figure born about 1783, apparently in Virginia. She was told nothing about the man, not even his sex. She was told only that one writing sample came from a person who was about 30 years old, and another when that same person was about 65 and suffering from rheumatism.
Her analysis closely paralleled the observations of two of Ball's contemporaries, a newspaperman and a judge, and several latter day biographers. [Link, via EOGN]