Okay, as Ron pointed out, one of my ideas would be for a LOT of clown loaches.
I would design it as a river system with directional power heads for current flow and aquascape it with a whole lot of cool driftwood (visualize tangled roots) and a bunch of live plants such as giant vals.
Now stock it with about 75 large clown loaches and a couple hundred Tiger Barbs, and a couple hundred Denisoni Barbs.