Personally, I don’t like anime Oreimo that much, in another word, My Sister Can't Be This Cute is not on my favorite anime list, because Kirino Kosaka makes the whole anime not that interesting in my eyes (no offense, just personal opinion). However, I like one kawaii girl in this series, her name is Ruri Gokou, she is also an Otaku (me too), she loves wearing gothic Lolita clothing based on the character from her favorite anime, and Ruri also likes cosplay, anime, video games and other things relate to otaku. In addition, Kuroneko is a tsundere-type girl.
Hence, when it comes to cosplay Oreimo Kuroneko, there are many lovely and beautiful anime costumes for girls. Although, Ruri is not the heroine of Ore no Imouto ga Konna ni Kawaii Wake ga Nai, there are lots of cosplayers interested into dressing up as her.