So here's an idea for you. A little off the wall perhaps but here we go.
How many times when you were out railfanning/trainspotting did you sit on a roadbridge and watch trains go underneath you? Quite often, I'll warrant and even more often as a child if you were like me. How often do you get to do that on a model railway/railroad? Not very often. I can only think of two, perhaps three layouts where the principal motion of the trains is front to back. Nearly all layouts have you watching trains pass across your field of view.
OK so there are severe logistical issues here concerning the location of your storage sidings. Which has to make for issues with an exhibition manager an 8'x2' layout is easier to place than a 2'x8' one. But I in my own bloody minded way think it could be solved.
Anyway, here's a mock up to tease your brain a bit.A loco would push some cars into the middle siding and proceed to switch them out to the sidings on either side replacing cars that would already be spotted there. A standard "inglenook" type switching operation. But all the switching moves would be to and from the viewer. There's not a lot room for folks to watch the layout end on with a 14" width as mocked up here. Even less when you consider the storage area will take up some of that. So some kind of concession needs to be made to letting people watch from the side. Perhaps having the layout open to viewers as far as the first buildings.
Having the storage sidings in front causes issues no doubt. But as I enjoy engaging the visitors in conversation (must be something to do with my accent) that wouldn't be an issue with me it could even form a part of the presentation.
Is it practical? I don't know. Its something to consider over the holiday weekend