I believe that this feature would be widely used by skin creators (including myself). I took a poll between my friends and 22/30 said that it would be a useful edition to osu. I am currently making a skin right now that could really use this feature, and I hope there are more people out there who agree with me. Let's make this happen osu community!
Edit: Sorry for not explaining how it would work. The audio would only be triggered by the pause command and isn't played such as pause-loop. It would be played as in some other games where a sound is played when clicking pause. For example, let's say that I wanted to have a cat meow when I click pause. All I would have to do would be to add a cat meow wav/mp3 into my skin as "pausesound".
Edit: Sorry for not explaining how it would work. The audio would only be triggered by the pause command and isn't played such as pause-loop. It would be played as in some other games where a sound is played when clicking pause. For example, let's say that I wanted to have a cat meow when I click pause. All I would have to do would be to add a cat meow wav/mp3 into my skin as "pausesound".