Oh sweet Jeebus, that sounds stupid enough for Lucas to do. I've always argued that vader couldn't know about his kids, because the Emperor and vader would have been hunting for them ever since. If this is in fact what he has in mind, it's some pretty weak sauce. Vader can pluck the knowledge of Leia's existence from Luke's mind (which right there tells us vader doesn't know about Leia) but the Emperor can't wrazzle the knowledge of Vader's kid/s out of him? I really hope that's not the direction this takes.