Wow, shittiest advice ever so far on this thread. /r/homeautomation should be straight up ashamed of the answers so far.

If you want a device that does exactly what you asked for, buy an Aeon Labs Doorbell. I mean, don't buy it as a doorbell as it's literally the worst product they've ever made. It's no-joke horrible as a doorbell. Seriously, farting into a shoebox and throwing the shoebox at your door works better than that pile of garbage. (The actual doorbell switch portion is unbelievably poorly designed.)

...but it will do exactly what you want. You can load mp3s onto it ("YO PICK UP YO DAMN PHONE!"), and it'll look like a regular light switch to your zwave controller. Kick it on to play the default mp3. Bada-bing, bada-boom, done. Exactly what you asked for.

But though that's what you asked for, I don't think that's your best bet. Even though the aeon labs is a doorbell, it's not wake-the-dead-from-rooms-away loud. (I told you, it's a horrible doorbell!) For that, what you need is a siren. A genuine honest-to-goodness zwave siren. Also looks like a light switch to your zwave controller. Turn it on, hold your ears, you're going to get noticed. (I haven't used that exact model, fwiw. The one I like and works great isn't compatible with wink, sadly.)