Good idea Bob, I'll take a drive at night and see how they go. Here's one I found with big reflectors: 20″ 240W Double Row Cree LED light bar, 10W series (Combo) - Led Light Bars Australia
My main concern is the IP rating. These are rated at IP67, which is reasonably good for protection against dust and water ingress. Everybody seems to worry most about projection, spread and Kelvin rating. I'm more concerned about drowning the things in river crossings.

