If you notice in my videos, the audio is really good (if I do say so myself , and I do). It doesn't fade or get louder as I move away from the camera or closer to it. What you don't realize is how much audio is NOT in the videos that was recorded by the camera. Here's how I do it.

http://www.youtube.com/watch?v=zSdC906CiY0

Great idea, and thanks for sharing!

I've had a similar idea for a while and I've yet to try it. It's more like and "iDea"!!!

Set my iPhone on the tripod, start video recording.
Take my wife's iphone, insert headphones with built-in mic (comes supplied with iPhone)
Use paperclip to attach makeshift lapel mic to shirt
Start voice record app and start recording

Then later use the techniques you described in your vid to sync the audio with the vid.

I just got to get around to trying it....