I like the polycarbonate sheet idea seeing as you have some nice wide euro braces to lay it on. You can go the inexpensive route with the corrugated plastic or spend a bit more for a nicer look and go with lexan. A jigsaw with a fine toothed blade will notch out grooves for the driftwood and light stands. Could do one big cover, or do it in two pieces. Long right side, and short, notched left side. Cut the pieces a little large and you wouldn't even need the clips.
92% of all statistics are made up on the spot.