Those are cool. As long as you got the right material and enough time, making one is not a bad idea.
What if instead of going with a metal tube with a oval type filter on the end of it. Stick with the stock setup plastic/rubber material for the tube, but take off the front of the filter box so that now only the square filter is exposed, and that is all you see. Granted you would have to use clamps to hold the filter in the box, but could something like that work? One more question. Do we really need that sensor to be plugged in, or is it safe to leave it unplugged?