I know people have mentioned him -- but definitely Dalembert is the guy I'd like to see.
Yes, he will be a bit pricey, but -- he's also a guy that has been a starter everywhere he has been and is one of the better defenders/rebounding big men in the league. He's also a good locker room guy. If Hibbert got injured or got into foul trouble(which is something he's known to do), Dalembert is a guy that can give you 30 minutes and actually contribute at a high level.
Besides, not like we have a lot of interior defense, anyway.