“bag of files”, meaning all PAL and NTSC files “thrown” inside a directory/disc?
That’s the idea.
I’d go with two (or more) disc, one PAL, one NTSC (possibly including two versions, where available).
I think splitting up PAL and NTSC content would be unhelpful - it’s far more user-friendly to organise by film, not format, hence the idea of just creating a repository of files in their original form (which, come to think of it, would now include 23.976 material such as my updated Giger’s Alien rip).
This would be well-suited to format-agnostic viewing, such as desktop playback, at any rate (and presumably media servers such as Plex and Kodi too, given that they can transcode on-the-fly for TV viewing).