My brother settled on a place and reserved it, a nice big place in North Topsail Beach, NC.
Thanks for the help everyone, we looked at a lot of great 9+ BR places up and down the coast but it came down to availability, it seems like you need to plan for these houses WELL in advance. It didn't hurt that the price of the one he picked was great.
http://www.vrbo.com/328973The marketing is a little annoying, they list it as an 11 BR place, but 2 of the "bedrooms" are pull out couches in the living rooms. But it is plenty big for us, and the pull outs will be nice if some of the potential drop-ins show up.