Hi I'd like to share what I made, and hopefully others will do the same in this topic...
First I made a speaker box, then crammed all the electronics inside.
Since I took this photo I have installed the amplifier and screwed the back on, so now it's fully working. Although you still have to open it up to change the memory stick (samples). It works well, but it's not quiet: you get a lot of electronic noise through the amp. Some heavy duty shielding is in order.
The next step is to modify the code to add a volume control, and possibly try to create some rudimentary effects like delay or flanger or reverb. I am a complete novice at this so I might not even try.
So, care to post what you've created?