Most of the refactoring features in Eclipse CDT are developed by people working and studying at the HSR Hochschule für Technik in Rapperswil Switzerland. There are students working on new refactorings and enhancements. After they had been reviewed they will be integrated into the official CDT.
For more information of the ongoing development get in contact with the leader of this projects Peter Sommerlad at the IFS.
Beside from this projects I think there is no other plugin/extension on the CDT platform.