For anyone that cares, someone finally found this doujin/offical artbook. It's got some sketch art, as well as some fanart, so if you're a fan of the series it's worth a look.
Rengeki_Storm said: For anyone that cares, someone finally found this doujin/offical artbook. It's got some sketch art, as well as some fanart, so if you're a fan of the series it's worth a look.