At the 2015 CES Show, Panasonic has unveiled their first prototype 4K Blu-ray player which strangely enough, doesn't have an optical drive yet. Either way, it's exciting to see a tangible step on the path to UHD discs for the home.
Source:
http://www.theverge.com/2015/1/5/7494863/panasonic-4k-blu-ray-player-prototype-ces-2015