some discussion of hardware hacks came up on the angstrom user's mailing list* so I thought people here would be interested.
It began with an off-the-cuff remark by Stanislav Brebec about stereo audio input, I asked for more information. he explained that the Zaurus x000 series are capable of stereo sound input, it's just that Sharp decided to ground one of the inputs, here's the HOW-TO
that message also goes on to discuss internal microphone, wifi and bluetooth - click on the "next message in thread" to see the follow-ons.
the hardware discussion then carries on in this thread:
* I am not on the dev's list as I got fed up with the bitching