Disney has two new massive cruise ships under construction which should be online by 2012. There have been a number of news articles on them shopping around for other ports but no mention of Panama City that I have seen.
http://www.mickeynews.com/News/DisplayPressRelease.asp_Q_id_E_7257Port
http://www.mickeynews.com/News/DisplayPressRelease.asp_Q_id_E_7257Port