Topic: Netflix US runs 4K HEVC/H.265 encoded video streams (production)
All of this being said, it is oriented on new TV's and smart boxes with build in hardware decoders. HEVC/H.265 bitrate of these streams around 15 Mbps, quality is superior to HD Netflix (1080p), but some Blu-ray titles on my Pioneer BDP-62F (in eu its BDP-450) still offer a cleaner image.
Still this my subjective opinion and with my LG 49UB8500 4K TV (@$1500 US), I feel quality is really amazing.
Knowing how big Netflix is on a streaming market in US, hardware decoders for HEVC/H.265 will be widespread before the end of the year.
I am not able to locate any details on internal mechanics of this decoders, but there is strong possibility that it can be used in home theater environment.
Before I paid ignorance to x265 due to lack of real progress compared to x264 options.