Well, the riocar.org download section is supposed to be exactly what you want, but many developers (myself included) have been too lazy to add our apps to the list.

Since there seems to be a lot more interest in the 3rd party apps now, I just went and added some links to the download section and broke things down into categories for games, apps, etc. Hopefully we can actively maintain this and make it the one-stop resource you're wishing for. Anyone know of any programs/add-ons that aren't in there now?