I contacted GoPro in January regarding the external microphone:
Reply from GoPro Support regarding external microphone.
From: GoPro <custsupport@gopro.com>
Subject: Case Update: 89637 - External Microphone
Date: January 9, 2011 1:51:13 PM EST
Currently, our developers and engineers are considering incorporating the audio in feature into the HERO cameras. However, no specifics regarding an ETA have been released.
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