I believe that H1 nitrogen steel is hardened into the 50's through work hardening. This is a rust proof steel used in cutlery.
I've heard that razor blades are hardened stacked together for HT. Obviously a deep hardening steel would be helpful (alloyed with manganese I believe?)
One cause of warping of hardened steel is that martensite (hard steel) is less dense than pearlite and other softer forms of steel. So hardening just the edge could possibly cause a warping issue. You'd certainly want to keep it very localized, perhaps laser? Many steels won't harden well with a quick heat (O1, A2, D2, M2 etc) because of carbon tied up in carbides, which require a longer soak at temp for the carbon to diffuse. Try 1095.
Some steels (D2 for example) are designed to retain austenite after quench to offset dimensional changes after HT.
One approach people take is to fixture the part and anneal it followed by sub critical anneals before quenching it. The part is heated and quenched bound between plates. This may not scale up well into production.
Another approach might be to fabricate most of the part from mild steel and braze or possibly just spot weld a cutting edge to it. Or perhaps like they assemble the teeth to bimetal bandsaw blades.
Just my .02
Nathan