I love Vocaloid songs, and MikuxLuka was the first pairing I was interested in. They're really great and I hope to see more of them.
On the other hand, I'm still waiting for Tianyi x Ling. We've got doujins for pairings with far more tenuous connections, but nothing for Tinayi x Ling, which is as official as Vocaloid pairings could get.