This is great.

What I'd love to see is a way to save multiple 'setups' for personal logistics so I can flip between them quickly (e.g. a 'factory construction' layout versus a 'attack biters' layout, vs a 'oil work' layout, 'space exploration' layout, etc.

Well, what I do, which is a bit tedious, is that I just copy it in a Todo List item, and then import from there.
How I would imagine this feature to get better is probably to have some sort of menu that you can use, which would include all your setups, and you could maybe clear the whole thing and create a new one, then save it along with an icon. This would be stored in the save file. But I don't have much knowledge of Factorio modding and also don't have time to implement this. Help of anyone able to do this is appreciated.

So I found "Logistic Request Manager" her on the mod portal which does most of what I'm looking for. A combo-mod that does both would be great :-)

Found this mod today. Does basically what you asked for.