I had a similar thought. Imagine a custom camera body to add a beam splitter for parallel sensors much like the original process with parallel film. One regular RGB sensor for the visible scene, and one monochromatic sensor for the narrow background spectrum.
But, I have no idea if the beam path could be devised to do this with commodity sensors and lenses, to minimize what must be bespoke.
New mirrorless designs and cinema cameras would have a hard time with this.
It would be easier to do what Fuji used to do: have four sensor sites, but instead of RGBW have RGBX where X is filtered to your wavelength, even then, demosaicing would create artifacts (like how you can get 10MP out of an old Nikon D1 but sharp edges are jaggy because the demosaic isn't uniform.
'At the time of its use, the sodium process yielded cleaner results than did bluescreen, which was subject to noticeable color spill (a blue tint around the edges of the matte). The increased accuracy allowed for the compositing of materials with finer detail, such as hair or Mary Poppins' veiled hat. It was also useful that the "sodium yellow" light (and its removal via the matte) had a negligible effect on human skin tones.[2] As the bluescreen process improved, the sodium vapor process was abandoned, its screen and lamps monopolizing huge studios and incurring a higher cost.'