This is a brand new minecraft redstone concept that is NOT A HORSE TELEPORTATION and IS multiplayer compadable. This method takes advantage of many minecraft 1.8 features to create a backpack in vanilla minecraft. To use this paste The command below into one command block and power it. using a Fast creation method this machine will be created Super quickly.

HOW TO GET A BACKPACK?
simply throw a leather and chest next to eachother on the ground and BAM! it will make a backpack

How to use a backpack?
hold the backpack item then right click, a GUI will pop up, then stop holding the backpack to be able to move again.

Why did u make this?
I was looking for a backpack in vanilla minecraft and all i found were people using the same "Teleport invisible horse"  method and these methods would require a seperate system and a seperate horse for EVERY person that wanted a backpack... NOT ANYMORE. this system uses minimal commandblocks so there is less lag, one system, and all you need to do to get a backpack is craft one on the ground... NO EXTRA COMMANDBLOCKS!!!!

Enough of me! heres the ONE command!

COMMAND: http://pastebin.com/PJdZ8P8S