Y'know, I've had a random thought bouncing around in the back of my mind. At one point, I had a Techworks VLB card with some weird video chip on it. And I'm thinking, it may have been the Falcon64... Sierra Semiconductor rings a bell there, and some Googling shows that Techworks did make a VLB card with the Falcon64.
Now, the reason I remember the thing at all is because of what a f__king PITA it was. I remember it being quite fast in both Win31 and DOS... when it worked. But I also remember screen corruption, random issues with a good many DOS games, and the fact that I could never get it to work in Win95.
So if that is indeed what I had, it would go a long way toward explaining why nobody's ever heard of the Falcon64 chipset, and why Sierra Semiconductor disappeared from the graphics card business.