I think this is what Smilodon was supposed to send me. There will be more to it than this I'm sure, but this is what I'm interested in.
The first of the songs is AKB with Kaze wa Fuiteru, and again I'm inclined to beilieve neither Matsui is involved. The moment they stop we go straight into SKE with Pareo wa Emerald. When that finishes we have a special combination AKB/SKE performance of Heavy Rotation, and in the time it took to sing Pareo wa Emerald the AKB girls are now in Nekogal costumes. Including Yui. What??? And of course if Yui isn't your cup of tea, ore even if she is and you enjoy other members as well (myself for example) there's Takahashi, Maea, Itano, Yuko, Mayuyu, Yukirin, Kitahara, Sae, Mariko an dprobably some others I'm forgetting. Icidnetally the first pictures of this event I found were on Mariko's blog, leading me on a hunt that really lasted from finding the actual title of the even and searching that on Youku (first result).