>Does anyone know of a tool to rename a class library, and update all the child instances of the used classes?

You can rename it in the class browser. As for maintenaining the hierarchy, you can do a small program which will search all the memo fields of your forms and VCXs for the word you are looking for. This is what we have done in our framework. So, whenever we change a class, we run the program after to synchronize all that.