The most massively multi-track event was a thorium conference in Chicago where many attendees wore a Clip+. Volunteers worked the room with cameras, and audio capture was decoupled from video capture. It looked like this... http://youtube.com/watch?v=co-vj_PSfL8
Despite having (higher quality) ZOOM H1n and wireless mics, I've continued to use the RockBox-ified Clip+ devices... even if H1n is running, the Clip+ serve as backup. There's no worry about interference or staying within wireless mic range.
The devices have 4GB capacity, and RockBox allows WAV capture. They'll run at least 5 hours before battery is depleted (with lots of storage left over). I would suggest sticking with 44kHz (mono) capture, as 48kHz is unreliable.
To get an idea of their sound quality, here is... http://youtu.be/ENH-jd6NhRc?t=3m21s
(And I would NOT recommend Clip+ with factory firmware... they only support 22kHz and levels are too high for clipping on people's collars.)"
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