Awesome I gonna try it! I've used Avidemux for that purpose, but thought about making something simpler with a Bash or Python script. But obviously you've done that now already :D
I hope this works for you :) It definitely scratches an itch for me. One I've had a long time.
ffmpeg can cut your video from start - end selection if wanting a fast comand line option :)
Yeah, which is basically what I do here. I just made a simple front-end for it.