TL;DW: turns out e-paper has become so good that a 1bpp image can be drawn, whithout ghosting or flashing, at 1/60 s. However, the controllers these displays ship with don't have the memory bandwidth like TFTs to enable this... until now thanks to an FPGA wizard. His monitor is a direct LCD replacement and can switch between high-quality (greyscale/high-color), fast (dithered black/color dots) and power-saving (like low-bandwidth controllers nowadays) modes automatically based on content and user preferences. Everything is open source with off-the-shelf panel and FPGA. The project is finished and is accepting preorders.
Consider watching despite this "spoiler", it's very cool.