In answering this question, I found out about the oiran, a class of high-status courtesans in 17th-18th century Japan. Some of the description of these people sounds very similar to the Companions who feature in Joss Whedon's TV show Firefly:
Compared to yūjo (prostitutes), whose primary attraction was their sexual favors, courtesans were first and foremost entertainers. In order to become an oiran, a woman had to be educated in a range of skills, including the traditional arts of sadō (Japanese tea ceremony), ikebana (flower arranging), and calligraphy. Oiran also learned to play the koto, shakuhachi, tsuzumi (hand drum), and shamisen. Clients also expected them to be well-read and able to converse and write with wit and elegance.
Within the pleasure quarters, courtesans' prestige was based on their beauty, character, education, and artistic ability, rather than their birth.
The highest rank of courtesan was the tayū (太夫?), followed by the kōshi (格子?). Unlike a common prostitute, the tayū had sufficient prestige to refuse clients. Her high status also made a tayū extremely pricey—a tayū's fee for one evening was between one ryo and one ryo three bu, well beyond a laborer's monthly wage and comparable to a shop assistant's annual salary.
-- Wikipedia, emphasis mine
Beyond this impressive array of circumstantial evidence, is there anything in canon (e.g. interviews with Whedon) to tell us whether or not the Companions of Firefly were based on the oiran, or for that matter on any other group in real-world society?