doesn't exist...may be some will be revealed at CES after the holidays
i have not compared 60Hz G-Sync/Adaptive-Sync vs 120Hz+ but I think the former is far more attainable even likely with next-gen GPUs...4K at high fps will be ridiculously taxing for years to come.
I just dream of a curved 21:9 4K with variable refresh rate and no backlight bleed