I am still waiting for Kirara Asuka + Akiho Yoshizawa to happen...
1) They are in the same company
2) Both of them are pretty famous in their own ways. Everyone know who Akiho Yoshizawa is and Kirara Asuka is pretty much a celebrity in Japan
3) Both of them are experience enough to put on a good performance.
4) S1 teased this duo before (magazine covers, the anniversary photo shoot..)
Just make it happen already, though the Aoi + Nami Hoshino in November would be pretty damn good too. (I like them more than RION)