Wow that's incredibly cool! I've been doing ADS-B with a tracker in my window using a pair of RTL-SDRs for more than a decade at this point. This seems like it could make a nice improvement to the Stratux project (ADS-B in / poor man's TCAS for small planes) as well.
We make a few devices already that work as a drop-in stratux replacement! An ultra low cost version based on m1421 is definitely on our minds but we're focusing on keeping up with our preorders for Winglet first. Most of the work on sensor integration should be able to be ported to an m1421 based receiver in the future if we decide to go that route.
https://pantsforbirds.com/product/adsbee-1090u/ https://pantsforbirds.com/product/adsbee-winglet/