i have a few in my hand right now and a bunch more if i looked for them,
look up the HD63484 datasheet
The chip offered a high-level command which reduced software development costs. In this way, the ACRTC converted logical x – y coordinates to physical frame buffer addresses. It supported 38 commands, including LINE, RECTANGLE, POLYLINE, POLYGON, CIRCLE, ELLIPSE, ARC, ELLIPSE ARC, FILLED RECTANGLE, PAINT, PATTERN and COPY. An on-chip 32-byte pattern RAM could be used for powerful graphic environments. Conditional drawing functions were available for drawing patterns, color mixing, and software windowing, and it supported clipping and hitting.
I have 2 sitting on my desk that are New old stock , there's about 100 chip tubes that i got from a surplus place 15 years ago and it looked like someone was building video computer systems of some type, all gold top ram chips of all sizes.
I live right next to tektronix and a bunch of other IC fabs that made all this custom high end gear back then and common at the surplus store , what about using an old tektronix mainframe as the display, build the rest on the side as a plugin module?