It's not a single, but a movie, called "Ningyougeki girudo" (Marionette guild)! Cover of the dvd and translation of the news found here follows:
"We've made you wait, this is BOC, bringing you news after a long time!
[Our new release] is an original mute movie, with only music and subtitles, which has been written by vocalist Fujiwara Motoo and produced by the director of BOC pvs, Banjou Hideichi! The theme song has also been written by Fujiwara Motoo and performed by BOC; this is a great work that was in the making for about one year! Please look forward to see it!"
OH GOD! An animated movie written by Fuji! Really, is there anything in the world that man can't do? Moreover, it's so likely that the theme song will be released as a single! And the art looks so lovely.
I'd preorder it right now (it only costs 2500 yen, less than 20 dollars) but neither yesasia nor cdjapan list it for preorder yet. ;__;
I'm so exciteeeeeed >___<