The official website for gdgd Fairies has revealed that KEI, the character designer for Hatsune Miku, has illustrated what the show's staff is roughly calling "a legit rip-off" for the cover of the first BD of the series. Somewhat fitting for a show with references to other shows and somewhat targeted at the NicoNico douga crowd in Japan, the cover for the first BD volume is based on the box art for vocaloid Hatsune Miku.
The site has named this the "Momone Piku (Temporary name)" version of the cover, written as "桃音ピク（仮称）" and notes "It'll be painful if more people mistake this for something else and accidentally purchase it."
Here is a side-by-side comparison of the two covers to see all the elements that have been borrowed:
The first Blu-ray comes out in January in Japan.
Image ©Crypton Future Media ©2nd Generation gdgd Fairies