I have also used MakeMKV to extract Adywan’s ANH DVD9 from his iso, and will happily put that on my Google drive for others to download if interested.
Something like this already exists - specifically, someone took the higher resolution PAL DVD9 video track (720x576), changed the framerate flag to 23.976fps, and muxed in the NTSC DVD9 Dolby Digital 5.1 audio track into an MKV.
It’s the best video quality available (highest resolution) combined with the best audio quality available (no PAL speedup) without any reencoding done to either track. I know it’s uploaded on MySpleen and has been shared elsewhere as well.