I would add that Bolivian Rams are considered to much hardier than German Blue Rams.
If this were my tank, I would put gravel in some areas with a lot of caves, hiding places spread out between large dividers (rocks, driftwood, etc.) to break up the tank into separate territories for the Rams, and I would add in some Apistogrammas (dwarf cichlids who are every bit as beautiful as the rams). Then between the little island territories I would fill the rest of the substrate with sand, and have a huge school of large cories - Bronze grow to about 3" and would be tougher than smaller varieties if they stumbled into a territory of a breeding pair. (I think the addition of the sand would allow the cories a large enough area to patrol along the bottom with their preferred media and they should stay away from the gravelly spots. I would also suggest building up the height of the gravelly areas slightly so that the cories recognize a clear difference between the sand and the gravel areas.
That would take care of your bottom area of the tank. For the mid and top levels, I would look into two (or maybe three) large shoals of fish that are very different in appearance from each other. Maybe a shoal of cardinal tetras (as Tizer said at least 20), and a shoal of black skirt tetras, red phantom tetras, or similar. I think in a tank that large, a tight shoaling variety like the black skirt tetra would be far more visually pleasing than a group of cherry barbs who barely shoal together. (I will also second the five banded barb recommendation. If they were readily available near me, I'd be getting a shoal of them! They look just as good as the tigers, but far less aggressive.)