One thing to note is that the Yamasaki panels have eDP internally. AMD have stated that the feature has been in cards for generations, it is likely that variable vblank can be supported by all cards (could the AMD rep clarify?). If the manufacturer for the panels edp chip uses the same chip in laptops, it may also support variable vblank.
Assuming the stars aligned and the right chip was in the panel, you could wire the edp directly up to dp, use drivers supporting freesync (which currently don't exist) and use a custom back light controller (should be easy enough with a PWM micro).
So, to say that the korean monitors will never do it is a step to far, but it would require someone with some motivation, and luck.