Hi-
I'd like to suggest a potentially popular use for your shield, that is difficult to do with existing shields. I am one of a growing group of Halloween Artists, who have recently discovered the Arduino. The number one thing we need for an arduino sound shield to do is to be able to play a stereo audio file, with one of the channels being used for audio output of a recorded voice, and the other channel containing an edited "click" track - basically short bursts of edited audio signal that are used by the Arduino to drive a servo in sync with the recorded voice. This allows you to drive the jaw of a talking skeleton or other figure, making it appear as if the prop is talking. I have seen one example online of someone using Ladyada's board for this, but I don't think it could do stereo, which meant it was driving the servo from the actual voice audio, which results in a very sloppy, unsatisfactory sync. By being able to edit your own signal track, with short bursts of audio signal, you can fine tune the movement, to make it very believable. Currently I use Scary Terry circuits from Cowalicious Designs to accomplish this, though it requires an external sound source. I use an iPod, in combo with the circuit to currently drive my projects. It would make much more sense to me to be able to use a sound shield with arduino, especially if the shield allowed the audio playback to in some way synced with other movements controlled by the arduino. For instance, it would be great if, using the arduino, You could use a servo to turn the head of the skeleton, then play one of the audio files, then turn the head again. My current system doesn't allow for me to synch the sound with other movement. Also, most Halloween enthusiasts, like myself, are not masters of writing code, which means if you could provide clear and easy to understand sketches for using your shield to operate talking props, you could pretty much corner the Halloween market.