This was the way of the first TMS34010 cards for Autocad (circa 1988). You'd have a EGA/VGA card for the host, and the graphics processor would drive the high-resolution graphics display. There were 50+ vendors with a 340 solution for the high-end, before SVGA. Later, vendors conceded to adding a VGA port integrated alongside.

In Karl Guttag's recent talk on the 34010 (VCFSW YouTube channel) he mentions being contacted by Bloomberg for their multi-up terminal. When it shipped in the early 90s, it was the first dual display system I'd seen. Wall Street later began buying 4-display Matrox cards.