I'm not saying dual-ported VRAM is "historically authentic"; I'm saying it's reasonably available, today, for homebrew projects.

was once commonly used / invented /in 1980 / first commercial use /in 1986 / Prior to the development of VRAM, dual-ported memory was quite expensive / Through the 1990s, many graphic subsystems used VRAM

Click to expand...

The linked article also goes into some depth about how to use it.

Meanwhile, here's DVI-D video out from an FPGA: http://hackaday.com/2012/08/03/moving-an-fpga-project-from-vga-to-dvi-d/

Perhaps outputting DVI-D is a worthwhile approach, whatever the base platform. Fewer pins, less messing about in the analog domain, and same signals as HDMI, so a simple adapter would let you hook up to a modern TV.