1. After struggling for hours with the implementation of trying to play .wav files off the microcontroller (in short--not worth it), we have come up with a more elegant solution: use the SCI serial interface to send MIDI commands to an external sampler/sequencer, the Roland SP404 (which I own).
For those who don't know, the 404 is a drum machine/music sampler sort of thing:
Basically, this will allow us practically unlimited playing time and high quality for samples, polyphony (so we can add sound effects on top of music, for example), and reduced foot print, as this will only require 1 microcontroller pin for a stereo setup. Granted, this does simplify the sound portion somewhat, but we would have only been able to store 10 seconds of poor quality .wav audio on the microcontroller, and the effort we put into that method thus far (10-15 hours) hadn't achieved any tangible results.
2. We have also ordered most of the rest of the parts:
-Cheap cordless drill for a DC motor