Bukkit Plugin: Turn Ingots Into Blocks Easily

I recently found another plugin request for a Bukkit plugin, and this one was pretty simple. The guy wanted a plugin that made it easier and faster to convert ingots and things to block form. For example, an easy way to convert 9 iron ingots to an iron block without using a crafting table. This is mostly used when trading iron, because it doesn't use up your inventory as much and is mostly used when trading for rare items like wither stars. It would be easier to say 7 blocks of iron then 64 iron ingots. I made a plugin that makes it so when you left click with more then 8 iron in your hand, it will convert it into blocks, giving you and remainders. Like 10 iron will give you one iron block and an iron ingot (9 iron = 1 iron block). It works with other things like Lapis Lazuli, Gold, Coal, and even diamonds if you get enough.