I made a joke on my Facebook page:
Soon after I decided to see if I could whip this up in Sencha Touch using Architect 2. It took me an hour (most time was spent searching for audio and images), and here it is. I call it Sleepy.Code:I'm going to make a Sleeping Sounds app for the iPhone with three settings: "White Noise", "Gentle Rain in the Forest", and "Carl Sagan reads anything"
See it at http://mattbaker.me/sleepy