I actually encountered a similar conundrum last week while trying to achieve better CGA support with an S3 Virge/GX. The palette wouldn't switch so Wizardry looked pretty bad. Obviously, running a CGA card alongside the VGA card doesn't work, but I did have an ATI CGA Wonder available. That card has a monchrome and CGA mode selector, as well as a CGA/monochrome monitor selector. So, running it in tandem with a VGA card I was able to run it as a Hercules card. I yanked the BIOS chip from the Virge, set the CGA Wonder to CGA mode, and voila, better CGA support.
For the more technically informed on such shenanigans, will I always need to remove the BIOS chip for this or can I install a switch to connect/disconnect a handful of power/VCC pins? Will that cause any issues with phantom power reaching the BIOS? Might I burn the apartment building to the ground?
I spend my days fighting with clunky software so I can afford to spend my evenings fighting with clunky hardware.