powerscol, I won't triple post the photo, but I just made them from some scrap 2 x 2 x 1/4" aluminum angle I had. I would have used steel, but didn't have any the right size, and since the alum. was about the right length, free, and easy to cut, as well, it was a no-brainer. It's heavy enough it doesn't flex/vibrate (resonate?) I did have to drill some holes in the hinge bracket of the ROPS for 1/4 - 28 bolts, but the integrity should be un-compromised by small holes there. I like the lights high enough to clear the plow, out enough to not hit the back of my head (with light) and light the front/sides well, yet not so far that they are likely to get whacked by stuff. I'd probably use the top underside of the ROPS if I usually had it up, but I can't because of my limited barn entrance height.
Eric makes a good point- look for 5000 K lights if you can find them. Too blue isn't so great to work in- especially if you're working in a snowy environment. Not that we've seen any here this year. It was almost 70 in NYC at Christmas. That's just wrong.