Ask HN: Is there a community of Apps Beta Testers?

I'm a iOS/Android Apps Developer and I always have the problem of looking for Beta Testers for the App before it is release and/or before releasing an update. This presents the challenge of using TestFlight and explaining over and over how to register and register devices. Plus my friends/family are not always interested in the App that I'm developing or their feedback is kind of biased.

I'm wondering if there is an organized community of people willing to test new apps categorized by type of app, device (iOS, Android, Web, Facebook), interests (art, beer, travel, sports) or preferences (FB connect, twitter).

If there is not such, i'm thinking about building something.