This is only my humble opinion.
When I first knew that the TyTn, followed by the next coming other HTC's PPCs (Trinity. Artemis), would not have the regular audio port anymore (Regardless the size, 2.5 mm or 3.5 mm), I was thinking they must be really stupid by taking that away. Since my first PPC, I have been always plug the audio/sound to my car stereo for MP3 and phone calls.
Then I tried to think about the logic, why would they take it away, they must have reasons, being such a high tech company. The most logical reason I can think of, they might want to design a good car kit /desktop cradle for it. Thus, by combining the audio port and the USB sync/charging port, they can create a cradle/car kit that would only have one connector to the PPC, instead of two connections/jacks: the USB and the audio pin. That might be a good idea, same idea like the earlier versions of the PPC, like Wallaby that had the serial connector that can be used for synching, charging, GPS, and audio input/output as well, all in the same connector.
But looking at the connector they made, the one posted above in the expansys, I'm kind of LOL really. 2 USB output, one for power, one for audio? Ha ha ha..
They /any third party, should have design a car cradle and a desktop cradle that not only have a regular USB for sync/power, but also just map out also the audio output to a regular 3.5 mm normal audio connection. And that cradle will be really useful and I would think many ppl will buy it. And for a plus side, just add a GPS module in the same car cradle unit, than its perfect solution.
Just my humble opinion...