Directly editing raw data in a DNG file prior to development

As far as I know, there is no publicly available program for blending sensor data of two shots before demosaicing and rastering it as a viewable picture.

While I could image this to be valuable in scientific fields, I cannot imagine any advantage apart from having to blend the data blindly vs seeing what I am doing after the base conversion.

So basically, there are no options for this unless you write your own raw data blender, which probably would take a lot of time and will not improve the image in any real way.

I can understand, that you want to skip the roundrtrip in a photo editing software and want to achieve something in your raw developer, that the program simply is not made for.