You'll be hard pressed to make a bar that is functionally better. This thing is pretty simple and adding gussets and heavier tubing will be offset by drilling safety holes in it. As far as we can see the stresses are in tension and compression only, so further stiffening probably won't make much difference in performance. I should point out the original prototype my partner came up with (he owned a Pathfinder at the time) was made from thin wall round tube, squashed flat on the ends, with a couple of holes drilled in it. It worked almost as well as our finished product.
I have a couple of Toyotas in the shop right now - a 89 Supra, it has a similar lower stress bar made from round tube, pressed flat on the ends with a couple of holes punched in the ends. An MR2 has a cross brace over the engine compartment- same round tube...
Feel free to make your own version, it could be done any number of ways. I could even visualize an adjustable bar with a couple of rod end bearings at each end, but again would it work any better? There is also a price point to consider - we made ours so cheaply that most people would just buy it. Some exotic version for a couple of hundred bucks would sit on the shelf a long time. By the away, our bar is TIG welded, and I had the end tabs laser cut - which, you have to admit, sounds very aerospace!
John