OMGoodness, yes! I've had that happen, and it makes me want to kick myself for not writing the idea when I first had it. Aargh! I agree that when it's happened, the other author has done a spectacular job, perhaps better than I would have done myself, but there is always that little pang of envy that I didn't do it when I first thought of, because if I do it now, it will seem like a rip off. Foo.