[Backtobasics]

Sheet of Lexan or plexiglass? This would allow the view through, and also could be attached by small angle iron pieces bolted to the back of the toolboxes. I picture a couple pieces, with a nut welded to the backsize that would allow a bolt to run through the plexiglass or Lexan. You could run a rod from side to side for support under the sheeting, and if it needs to come off, you zip out the bolts, move the sheeting, and slid the bolts back into the angle iron, so they don't get lost. You could even position the angle iron pieces the same width away, that your side to side supports could be bolted front to back, so they aren't in the way or get lost too...