This looks exactly like how I would want it as well! Thanks for taking the time to mock this up.
Like you, I am really interested in such a layout. I like, also, the idea that as a plugin you could toggle this on or off. So you could go back to the more compact, “standard” file explorer if you wanted, or could use this layout.
Obsidian would also replace Ulysses for me if we had this! I think a three pane view like this is particularly well-suited to a certain kind of longer-form writing. Ulysses employs the metaphor of “sheets” that you can glue together. That is easily translatable to internal liniks and embeds in Obsidian. What we need is just this alternative way of looking at the files.
And I agree, a built-in ability to drag-around to custom sort would be really great too.
Who do we know in the developer community that could pull this off???