Right here in this thread and hope that Patchou sees this
Though, I must say I personaly don't think this will be added anytime soon. The reason being:
A) you can make something with scripts for this.
B) When this is added, it means that for each individual status you need to be able to set if you want Plus!-sounds to be played or not. This means a relative big chance in the GUI. And such changes don't happen a lot.