Books allow client to apply any name and enchantment

when you sign a writeable book you can give it NBT tags of enchantments.

its accepted by all servers 1.3.2 and maybe 1.4.2

as you can see in this pastebin
http://pastebin.com/LUd6Eg4k

var8 = "MC|BSign";
is where the sends the enchantment to the server
public int[] enchantmentID = {-1,-1,-1,-1,-1};
public int[] enchantmentLvl =

{32767,32767,32767,32767,32767}

; is where the enchantment is decided ( by client)
this.fontRenderer.drawString(var7, var5 + 36 + (116 - var10) / 2, var6 + 48, 0);
String var11 = "Enchantment 1\n - \n" +
"EnchantMent 2\n - \n" +
"\nEnchantment 3\n - \n" +
"\nEnchantment 4\n - \n" +
"\nEnchantment 5";
adds the new lines for the text of the enchants
}
heres a video of the exploit in use
http://www.youtube.com/watch?v=zpIldcK3ma4&feature=youtu.be

sorry about the crap PC
tested on 1.3.2 but not 1.4.2