I was not able to find it after a cursory look, I did stumble across the Home2Shortcut app and it allowed me to program the double tap...
It's flaky and not a real solution. It does allow you to set an action on double tap, but if you tap quickly, it still launches s-voice. Even if you have the s-voice home button launch check box off, if you double tap normally, s-voice will still intercept the intent and drop it. With Home2Shortcut, you can set the delay between first and second press to long or very long and then if you double tap slower, it will launch the app you pick, but it's flaky and doesn't always work. Additionally, it means an even long delay when you press a single home tap to get out of an app into the home screen. With very long set, it's about 2 seconds.
The real solution will be to set the action in the double_tap field in Settings.DB with the sqlite editor, but unfortunately that requires root and the non flash method of root no longer works on the S3 with JB. Hopefully the devs over at xda will figure it out soon.