The next version of the Apple TV is opening up to support third-party iOS apps ('tvOS' variant). If folks are interested, it's possible to sign up for possibly getting an early-access dev unit: https://developer.apple.com/tvos/
The final device should release some time in October if I understood the keynote announcements correctly.
(Note that the new device will have an A8 processor which should be powerful enough to decode WebM videos, but that'll require finishing up T91689 / T68722 since there's still no native support for WebM/VP8/VP9 in iOS 9.)