This is a good idea but it would defeat the purpose of having all the game data on a pixel image :( I'm aware the sound effects are annoying though, I plan to improve them.
Another approach would be to store the sound effects as WAV files in a 'sfx' folder than Pix64 load at start up. You then are free to put whichever WV file in your local Pix64 'sfx' folder.