The Ultimate Idoru
Eguchi Aimi is not a real person, but a composite from members of the J-pop group AKB48. Tokyo Hive explains, "The features of Eguchi’s face were taken from the members, which consists of Oshima Yuko (hair/body), Takahashi Minami (outline), Maeda Atsuko (eyes), Watanabe Mayu (eyebrows), Itano Tomomi (nose), and Shinoda Mariko (mouth). Twelfth generation AKB48 member Sasaki Yukari is confirmed to be the source of her voice as well.” via William Gibson, (of course)