I did not see an single method that took a Comparator so I think you
are SOL for a simple implementation.

You will have to study the code for a FileSystemView and clone Sun's
windowsFileSystemView and modify the code where in uses File.listFiles
to insert a sort after.

I noticed some code that made me feel a little queasy poking around.
What the heck is this??

FileSystemView

 public File getChild(File parent, String fileName) {
       if (parent instanceof ShellFolder) {
           File[] children = getFiles(parent, false);
           for (int i = 0; i < children.length; i++) {
               if (children[i].getName().equals(fileName)) {
                   return children[i];
               }
           }
       }
       return createFileObject(parent, fileName);
   }