NVIDIA makes a reference design for a variable vblank TN display and manufacturers have their customized copies out in months.
In the mean time cheap as chips 4K and 120 Hz capable (not at the same time, 1080p at 120 Hz) MVA panels have been available for over a year now and still the only bloody way to get one in the US is in a TV from some fly by night brand and in the EU through imports. You could make a 4K/120Hz monitor with a scanning backlight for minimum investment and sell them at prices almost guaranteed to sell.
In the mean time cheap as chips 4K and 120 Hz capable (not at the same time, 1080p at 120 Hz) MVA panels have been available for over a year now and still the only bloody way to get one in the US is in a TV from some fly by night brand and in the EU through imports. You could make a 4K/120Hz monitor with a scanning backlight for minimum investment and sell them at prices almost guaranteed to sell.