Open-top operation idea - does anyone do this?

[Triplex]

I was trying to draw a double-deck layout, and I realized a problem. I was struggling to figure how to handle open-top traffic. I didn't want to force producers and consumers to be located on the same deck. Ideally, mines would be located on the upper deck, reflecting how they're often in hilly/mountain regions in reality. Consumers would be on the lower deck. No way to arrange a LI/EO setup. It would also be ideal to not require on-layout destinations for all loads. Storing complete loaded or empty trains in staging wasn't a new idea, but it took a major step to realize that I could do something similar at industries. That is, hidden tracks at a mine, as in a LI/EO setup, that go nowhere. They have enough space to store the empties switched into the "loader" and the pre-stocked loaded cars. Only problem is the re-stocking of cars between sessions, but I don't know why that's so essential to avoid that I never seriously considered the idea until recently.

Now that I think about it, I have seen this concept used, though I don't remember it with large quantities of open-tops. It's basically the same idea as a hidden interchange track.

I'm not sure what to ask, except - Have any of you seen (or built) a layout that uses this technique for loads and empties? (It doesn't have to be double-deck; that's just the circumstance that led me to realize this.)