.NET Reflector Add-in for renaming

Is there an existing .NET Reflector add-in that allows renaming of namespaces/classes/methods etc?

Not for Reflector, but there is an add-in called ReSharper that plugs into VS itself, and has a lot of neat little refactoring tricks including "safe" renaming on many levels. you can find it at www.jetbrains.com.

Use Reflexil add-ins. It allow you to rename, edit, add, remove code, class, members, etc