Craftable laser blocks that emit lasers. These will require many valuable materials and will provide a protection around your home. Obsidian, redstone, diamonds and gold may be used in creation since there are not many uses for these items. Lasers will be a instant kill but will require many resources to finally make one. To balance it out even more, maybe it would burn out every once in awhile and you have to fix it with obsidian or something.
UM! YAH! YAH!