Sekiran-un Graffiti (積乱雲グラフィティ) by ryo (supercell) is “available on the US Amazon MP3 store for $5″:http://www.amazon.com/Sekiranun-Graffiti-Feat-Hatsune-Fallin/dp/B005HAOSXS/.

Kinda catchy. The B-side is pretty decent, too.