> if you can live with the fact that the destination object has > to inherit MarshalByRefObject,
This isn't a strict necessity. The constructor for RealProxy takes a type that must be MBR. System.MarshalByRefObject works very nicely for this purpose. It works especially well for those classes you want to tweak but don't inherit from System.MarshalByRefObject. Of course, depending on what you want to do, this may not be an option, and I'm not familiar with the originally referenced Java class... You can read messages from the DOTNET archive, unsubscribe from DOTNET, or subscribe to other DevelopMentor lists at http://discuss.develop.com.
