Well, sorry to disappoint, but C and I will be keeping our last names when we are legally married. That's not because our friends didn't suggest a litany of interesting/hilarious last names (e.g. "Mustang").
C and I contacted our lawyer in Illinois to ask if the name change would be recognized outside Iowa. He said no. For a name change to be recognized, he said it must occur in the county in which we presently reside.
So, rather than walk into the logistical nightmare of having illegal last names, we have decided to stick with our present names. For now.
But just you wait. Once those babies are on the way, we may be calling on you once again for your ideas :-)