For the display, two things are mandatory. Video output drivers and blanking.

Each vga color wire is terminated by a 75R resistor,  hence the need for special op-amp able to drive such high load. I'm using the LM6181 op amp which seems to be now obsolete. I may switch for the MAX4392 or equivalent if I need to.

The blanking is done by using the horizontal sync signal. Documentations show a particular signal timing for the blanking of colors but my tests gave the expected result on two different monitors. Maybe the monitors create the needed blanking.

Considering the limited space in the case I'll probably use (an old tool box) a switch is present to send a monochrome signal, letting the color's VCA (if there's any) be used for others tasks. Monochrome is achieved by driving the RGB signals with the same signal (all three colors at full brightness give white).

For the prototyping stage a cheap vga signal generator from ebay is used. It gives timing signals and color input. It'll be replaced by a STM32f0 microcontroller.