Oh I agree Fred, GPS satellites have all kinds of special, and general, relativity going on. If they want to nail this one down they are going to have to lay a lot of fiber-optic cable. On the supernova thing, we are assuming that the photons and neutrinos left at the same time and for the neutrinos to arrive early at all, even a little bit, is a bit of a problem I think. Even if we end up increasing the speed limit of the universe a little, it will be interesting see to what ramifications it might have. Neutrinos help make up "Dark Matter" and may comprise up to 20% of the matter in the known universe. And with science, all you need is that little foot in the door, and then you can exploit it.
t-dub