I don't believe that you need any additional hardware to do what we just saw. Physics is math. Math coprocessors are already part of any decent PCs. And now the trick is to stack CPU cores to keep adding performance where the GHz are getting harder to come by. So dedicate one or two of them (quad ones around the corner, right?) to help along as well.
I remember when 3D graphics cards started to appear. The technology of 3D games at the time was to compute and rasterize 3D into 2D with the CPU, into very limited resolution and color space. It was instantly obvious then that offloading 3D transformations and 2D projections and rasterization into a separate computer on a card was the way of the future. Seeing something run smoothly in thousands of colors at a high res was the proverbial picture that's worth 1000 words. It's so dramatic because it really is a handoff--after the 3D computer on a card gets it, it never touches the PC bus or CPU again. The input to the card gets processed by the card, and goes straight to its own independent output, the screen.
This business of physics cards does not in any way come close to that feeling of immediate need, and can't be truly separate from the PC side, since the results of the physics functions have to be returned to the running app code anyway. Unlike "create a display from these data and don't bother me", a physics engine is an integral part of the mainline code. Its results affect the mainline events, so it can't be handed off and ignored thereafter.
I just don't see it, other than as someone's wet dream, being pushed by their propaganda machine with all effort it can exert.