Who provides an auto trans shifter with readout for position in rear view mirror?

There isn't a commercially available product that provides an automatic transmission shifter position readout displayed directly in the rearview mirror. Rearview mirrors are primarily designed for visual observation, not for displaying supplemental information like transmission gear selection. While some vehicles display gear selection on the instrument cluster or head-up display, integrating it into a rearview mirror is not a standard feature or aftermarket modification readily available.