I admit when I read your thread title I felt a pang of jealousy, so clinically I think I must be insane. We are thinking about trying for a third child, and my husband admits to hoping for twins again. Hopefully this will jinx it: hey universe, we really want another set of twins...ha, ha, ha.
Enjoy! I'm sure it will be fun to see you daughters interact with the new babies. They are going to be convinced babies come in sets of two!