I know, I know, whenever you have a good idea, chances are someone else had it long before you. This seems especially true in philosophy. Hell, it's probably a natural law the universe is set to run by - a variation of Murphy's law perhaps.
But what's really annoying about this one is that I was so damn close. I'm talking about my counter-argument to Van Inwagen, which denies his premise 4 (rather than the usual 5 or 6). I was quite proud of that. But it turns out someone else beat me to it.
Benjamin Schnieder, in the Feb 2004 volume of the Philosophical Studies journal, makes a depressingly similar argument to mine. How about that... just 3 months out! Damn.
Update: Hmm, I've found another article from 1977 based around the same core idea. Looks like it's not so new after all. Oh well. Maybe next time...
[Update 2: edited to fix errors and remove a joke that was in poor taste.]