According to an anonymous tipster, the official launch of Android 4.3 may be coming very soon. This tipster indicated the latest version of Android is already on most of the devices within Google. This same leaker let it be known that Google also plans to bring most of their core apps to the Google Play Store in/around the same time-frame. Finally, this same source indicated that a new YouTube update would be coming soon, but it would released separately in the Google Play Store, not with the Android 4.3 update. Interestingly, this new YouTube update will bring several new features, most notably the ability to multitask.
We haven't been able to get any third party corroboration on this one yet, but the source of this leak has been reliable in the past. Stay tuned!