It's been a long time since this was ever made, but I'm looking to find the Ringetsu Visual Fan Book, the art book for the VN series Ringetsu and Shin Ringetsu, by Selen.
Japanese title: 燐月-リンゲツ-ビジュアルファンブック
Artist: Kawagishi Keitarou (of Majikoi fame)
Publisher: Kill Time Communication...