Working on a mine site, the bayonet mount mast with red flag & reflective tape are a store stock item. You can even get the ones with the red light at the top of the mast - these would be good for crossing sand dunes at night (says he with tongue in cheek).
Otherwise, how would a very long length of very strong fishing line (or similar) tied to bullbar with red helium-filled balloon attached to other end grab your fancy.
I agree with some of the other postings - can't see the point of these things in sand dunes. But they do work bloody well on heap leach ramps at gold mine when other d*ckheads forget to call up on radio. Saved me running over the top of a Hilux a couple of weeks ago. And that could have been serious (for me), because I was driving the Prado and not the Landy.

