The hard part of making a scoop would be creating the "funnel" to mount it to the bottom of the box. I was thinking that an A/C/heating duct contractor could help design something in that regard. Then use some 6" oval ducting to route to the bumper with a custom scoop.
Figure out how to make that stuff out of plastic, and you'd be golden.
Figure out how to make that stuff out of plastic, and you'd be golden.