tl; dr: Acer S271HL software-only non-permanent 60Hz v-synchronizeed strobed backlight with brightness control, LCD overdrive reduction, and also more control over normal PWM dimming, using standard i2c bus
I did some probing and figured out how to configure a strobing backlight and reduce overdrive/RTC to be almost perfect on my Acer S271HL LED monitor, all through DDC/CI writes over the i2c bus, without any hardware modifications. The PC has complete control over all the hundreds of registers in the driver chip. My previous hardware modification is unnecessary. Things can be adjusted in real-time and no permanent changes are made to the monitor firmware.
I'm doing this on Linux at the moment with the i2c-dev library, though it should work on any OS that gives low-level i2c control. Or, if you modified a video cable to use an Arduino, FTDI, etc. for the two i2c lines, you wouldn't need OS support (I used this approach first, then made it work on the standard Linux library).
This approach should work (with some adjustments) on many LED LCDs that use the Realtek driver chip. With some work this could allow a lot of people to use common LED LCD monitors to get blur-free 60Hz video. I've considered modifying the firmware, but that is risky and would be very specific to this monitor model and build. It's actually easier to have the PC reconfigure it on the fly, rather than having to go through the tedious OSD and controls on the monitor.
One other minor feature is that the backlight can also be dimmed more than the OSD allows, good for night time use where you don't want an overly-bright screen. The PWM rate can also be increased beyond the standard 1kHz, for whatever it's worth.
With strobing, eye-tracking gives virtually no blur:
Ghosting is very faint with my overdrive adjustment:
The stock overdrive settings cause bad overshoot:Album
with high-res pictures.