improved fs_rom

While working on my own "Sculpt" scenario, I saw that the fs_rom server still doesn't allow using multiple directories as sources. Being able to separate the executables, libraries, and config files would be very helpful for organizing the filesystem and providing shared libraries to programs without exposing the configuration files as well. Is there a way to do this with the components currently available, or should fs_rom (or some other component) be modified to enable ROM file separation?