This post seem interesting... Though I would need more details. If you don't mind just PM me about more information on this project and I will be willing to help! Also I do Minecraft animations if that a difference.
I know it not all about the money. I really don't want to make money, it's just that I'm low on cash and I'm trying to make at least 27$ so I can have an official Minecraft account. Right now I'm using an auto updating cracked version.
I love the idea, though I would have no idea on how to code this in. I guess I could add a vacuum animation and it opens the exorcism tab. I could also add a faint glow like a redstone torch when you put the Backpack on. I might implement this. If I do I'll give you credit. Also I'll PM you and Kunaty when I post the download link.
Zombie, Ninja, Steve, and a creeper all in one skin. On the shirt you can make holes that reveal his creeper skin and then and 1/2 Ninja face 1/2 Zombie face and then do the rest as Steve.