Jesse (MysteryMe??) had one over his 57 rimless (it's for sale currently, I think). I seem to remember him saying that he built the canopy. He might be a good one to reach out to.
I built a hanging one for my 60g out of galvanized water pipe. It's attached to the stand with saddle clamps, so you can adjust the height. I also left the shorter uprights on top of the canopy a bit loose, so you can swing the canopy to the side to provide some additional room to do maintenance inside the tank.
The galvanized look is not for everyone, but it went with the look I was going for...style and function. You could certainly paint it black, if you chose to.