Mystery Port on DS?

It is said that The Mystery port on the Nintendo DS could be be an External Headset and Headphone Combination. Could it be true? Last week Cube-Europes handheld team posted some interesting pictures of the E3 Nintendo DS without its case. After rampant speculation over the recent official word of a still-undiscussed port on the system, the European site dug into its secret documentation, supported by slides of the E3 presentation, to convincingly show that the port is designed for an external microphone.

The apparently planned headset microphone comes as no surprise: things can get noisy on the road, and headset microphones are much better at picking up voices. Nintendo has been questioned about such an accessory in the past, but never provided a firm response.
Source: PlanetGamecube