I just had a relevation- spoilers ahead:
Anyone watch the SciFi Inside, which is now on iTunes? A couple things that I'm trying to piece together. First, We know that Gina (#6) kills Cain. There are some new photographs and that's the wide rumor. Second, in the SciFi Inside, the acress who plays Six mentioned that she kills a Cylon. The images that I've seen show Gina in a Colonial Uniform with a gun to Cain. I'd been wondering how she got the uniform and gun, and it struck me - She somehow convinces Baltar that Cain is a Cylon, and pursuades him to help her, and she carries it out. Cain as a Cylon would make sense, why the Pegaus escaped destruction in the first place, but she's also creating huge problems for the fleet, and is rumored to have abandoned her own civilian fleet.