On another note, a working version for 1.7.2 was just released, so if you're playing in the past, there it is!
I recommend anyone who is having a hard time for the container and GUI to download this. This is a very good reference as it is light in code and easy to understand.
It also helps with multiplayer, if you want a sword for each individual player, you can name the swords, but also have a desired colour and effect. A suggestion for the glowstone dust variant could be glow in the dark or be able to break glass with the sword and loot it. Just an idea.