Hi,
What can I say, great minds think alike? I never saw this thread and coincidentally
a very similar idea today, a month later. Wierd. Well I updated my page to credit you and hopefully this will lead to more discussion that might help you. Seems like a doable project, though I am not sure about how easy it is to spoof my version which does not use a hash or domain. Also someone above mentioned the need to send an error response back but I am not convinced he's right.