@Raymond, Can I suggest that you fix the error that I pointed out in your summary of the Wikipedia article?
> "The Wikipedia article for GUID contains primary research which suggests that future and previous GUIDs can be predicted based on knowledge of the random number generator state, since the generator is not cryptographically strong."
Wrong. The predictability does not occur because the generator is not cryptographically strong. Nor does the referenced article say that. It occurs because if you can obtain the full internal state of *any* PRNG - cryptographically strong or otherwise - you can certainly predict all following outputs, and possible the previous ones.
So an accurate summary would be more like this: "The Wikipedia article for GUID contains primary research which suggests that the sequence of V4 GUIDs is pseudo random, ie. based on a deterministic PRNG. Therefore, given full knowledge of the internal state, it is possible to predict all previous and subsequent values."