I think these ceramic knives are close, but missing the obvious fix: ceramet.
Ceramet is a material that currently exists, has great hardness and tensile strength, but also is relatively tough.
There are several variants of this material, but a good way to think about it is as a ceramic with a metalic matrix, often silicon boride ceramic and aluminum for the metal matrix I believe.
It was developed as armor for aircraft I believe, and I saw a film that showed a piece that appeared to be about .5 inches thick take a hit from a medium caliber anti-aircraft cannon and suffer only deformation, no actual penetration.
Anyway, bitch'n material and would probably make a pretty good knife. I'm sure it's expensive, and I can't find a source for it, but there's got to be a market for it with people spending hundreds of dollars on collector's knives that offer little advantage in way of material or design. This stuff would really be something no and different. Be a pain in the butt to sharpen though, but what do you want?