Inspired by this fanart and (somewhat) by another SZS × K-On! mix from Youtube. (http://www.youtube.com/watch?v=erfNqxVydTo)
It sounds awkward at first but it gets better as it progresses, I guess.
(I'm not sure whether I should put this in the Junk Pile or not.)
[ Original songs ]
● Vocals: "Kuusou Rumba" by Ootsuki Kenji, Inoue Marina, Kobayashi Yuu, Nonaka Ai, Sawashiro Miyuki & Shintani Ryouko (anime: Zoku Sayonara Zetsubou Sensei): tempo 176 → 181 BPM
● Instrumental: "Don't say 'lazy'" by Toyosaki Aki, Hisaka Youko, Satou Satomi & Kotobuki Minako (anime: K-On!): pitch +2