That... went faster than I thought.

It's now running on the PCB (this FPGA is a 144 TQFP Lattice MachXO LCMXO1200C), and I even am generating the black and white refreshes by writing to/reading from the SRAM. Here's the hardware; it should be safe to build now: https://github.com/dqydj/PaperBack_EPaper_Display/tree/master/hardware/PaperBack_Converter

I'm going to rush ahead and see if I can get it to MVP instead of posting now. If I get stuck I'll upload the VHDL driving the above... but let me take a shot at getting VGA going(!).