It could happen.
There are rumors (according to Bloomberg) that the two have been chatting about it. Skype users can already call and SMS Facebook friends, making video the next logical next step.
Personally, this feels like a natural extension of Skype’s current incarnation as a consumer video calling tool. I assume it would take a lot less overhauling than their stated plans to work with Citrix’s GoToMeeting to make a complete collaboration suite. Even if I’m wrong about that, I feel the audience fit is better.