Sharp says 4K/UHD resolutions are already not good enough-- as seen at CES 2015, the company's 85-inch Aquos Beyond 4K UHD TV (yes, that's the actual name) claims to produce images reaching near-8K (7680x4320) quality.
Such image quality is achieved via Pixel Splitting, a self-descriptive process that essentially cuts pixels in half vertically, creating so-called "subpixels" with individual colour values. As a result the TV produces 66 million subpixels for effective 8K resolution.