Question of the day: non-Newtonian armour?

When you mix cornflour with water, it acts like a liquid until you hit it – then it turns into a solid, just for a moment. So solid, that if you fill a bath with it you can jump up and down on it and not sink, but as soon as you stop jumping it turns back into liquid and you sink.

So, my question is, could you use this as a way of creating body armour that would allow you move around but go super-hard when something hit it?  Could chemical engineering come up with a way of making a fabric that consisted of loads of tiny pockets of non-newtonian goo that could allow easy movement but would still stop a bullet?

Does this already exist? Would it work as body armour, or would it have to be a bullet proof blanket?

Tell me what you think in a comment!