I know it's not exactly what your looking for, but there is a screen saver program, yes screen saver, that let you do tons of other things. One of them was mapping sound effects to any/every key on the keyboard.
You could turn off all the other programs, like the screen saver, and it was creadted to be loaded from start up and run in the background.
It was really cool and I wish I could really REALLY remember what it was called.... 
Trust me, when I do, I'll post...
You ever figure out what that program was called?
