Suafe is a Subversion User Authorization File Editor, which does exactly what the name implies. It is a Java Swing GUI application that helps with editing of authz files. Suafe also has comprehensive command line options that allow it to be used via scripts to modify and query authz files for information.
Suafe has been around and used for a few years, but new features are on the way. Adding support for aliases is on the top of the list as is changing the GUI to utilize the new, sister project suafe-api.