The Nexus 7: Google ships a tablet

Well, new data is continuously transmitted over the DVI/HDMI/DP/VGA/what-have-you. It's probably still the case that 8-bit color resolution is still reached by shifting between the fundamental color's 6-bit values in some predetermined pattern that averages to the right brightness value over time. The backlight is probably rapidly toggled between full power and no power duty cycle according to desired brightness level.

So yes. I expect there's a lot of what we'd call refreshing, one way or other.