Biology: Nucleogenesis

I've read a couple interesting articles recently discussing theories as to how the nucleus of cells evolved. I must say that I support the idea of a viral origin. It seems the most logical though I can't quite see how the recently discovered mimivirus relates to all this except to point out that really complex virus can evolve. But as a central principle I can easily imagine a virus that evolves to take over simple single celled organisms that don't have a nucleus. And from there it's easy to imagine it mutating to become truly symbiotic; such that only reproduces during cell division. And finally from there it's viral envelope evolves into a more useful nuclear envelope. It's quite a startling idea to imagine that we evolved so directly from the ancestral merger of virus and scum. Quite possibly foreshadowing the invention of sex.