Thank you for the great article on enums! I've never used a language with them, but after your examples, I'll agree they would be very useful if built into Java.
I just happened to see a link to JSR 201 on theServerSide.com with the mention of enumerations, and had to see if they really were looking at adding enums to Java, and it appears they are!
I did a Google Search and found a lot of people talking about JSR 201. The top link (isn't Google good!) discussed a project that pre-processes files to create .java files (similar to your enum solution) and allows any extension to the Java language.