<i>Mayflower Madame</i> is an autobiographical piece with some info related to this topic.  She had a few women working for her who were paid $500/hr (iirc), in part because they were just so much more beautiful than the others.  The book also has some hilarious tales, for example of gay men hiring the same girl over and over to be a fake gf for weddings and other family events.  In one case, the family liked the girl so much, she and the gay man had to stage a dramatic break-up because his family wanted him to marry her.   The author had insider information and didn't have to do a survey to get her numbers (or her explanations as to why X amount was charged), so they are probably a bit more reliable (though dated at this point).