The picture below is courtesy of Right Wing News
I doubt that any sort of large split will happen in either church. It's more likely to happen in Missouri... but less likely in the ELCA.
And also lately I read about a new "synod" that is comprised of congregations who broke off from the ELCA because of the gay issue.
But guess what? They have female pastors. They aren't conservative. That's why you won't be seeing ELCA congregations joining the LCMS any time soon.
I wanted a chance to respond to this comment made by Brian, but I am not sure how much space my reply is going to take, so I'm placing it here. The last time I talked to Chris (I have another friend attending the ELCA seminary in Minneapolis that I've known for a while who happens to be named Chris), he thought that chances were the ELCA was going to split into four synods. I don't know how much things have changed since I last talked to him (it has been a while), but things don't look good. It wouldn't surprise me if some of the more conservative elements within the ELCA merged with our liberals to form a new synod. I personally believe that the conservatives will start talking with WELS and the ELS to try to form either a new synodical conference or a new synod. As a matter of fact, if we were smart, we would start talking to them unofficially right now.