Hey Kroc, I know it's been a while. I recently got back to Sonic 1 again, but I feel that I've found all the music & sound effect bytes, and I'm gonna discontinue looking for more stuff. I did however, find some unused sound effects in the game: http://www.youtube.com/watch?v=1fQUTdRZzF4
I will be sure to give you the map so you can add some of my findings onto your main map.
~ Penta Penguin ~